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2016-03-03hpfs: don't truncate the file when delete failsMikulas Patocka
commit b6853f78e763d42c7a158d8de3549c9827c604ab upstream. The delete opration can allocate additional space on the HPFS filesystem due to btree split. The HPFS driver checks in advance if there is available space, so that it won't corrupt the btree if we run out of space during splitting. If there is not enough available space, the HPFS driver attempted to truncate the file, but this results in a deadlock since the commit 7dd29d8d865efdb00c0542a5d2c87af8c52ea6c7 ("HPFS: Introduce a global mutex and lock it on every callback from VFS"). This patch removes the code that tries to truncate the file and -ENOSPC is returned instead. If the user hits -ENOSPC on delete, he should try to delete other files (that are stored in a leaf btree node), so that the delete operation will make some space for deleting the file stored in non-leaf btree node. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03do_last(): ELOOP failure exit should be done after leaving RCU modeAl Viro
commit 5129fa482b16615fd4464d2f5d23acb1b7056c66 upstream. ... or we risk seeing a bogus value of d_is_symlink() there. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03should_follow_link(): validate ->d_seq after having decided to followAl Viro
commit a7f775428b8f5808815c0e3004020cedb94cbe3b upstream. ... otherwise d_is_symlink() above might have nothing to do with the inode value we've got. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03do_last(): don't let a bogus return value from ->open() et.al. to confuse usAl Viro
commit c80567c82ae4814a41287618e315a60ecf513be6 upstream. ... into returning a positive to path_openat(), which would interpret that as "symlink had been encountered" and proceed to corrupt memory, etc. It can only happen due to a bug in some ->open() instance or in some LSM hook, etc., so we report any such event *and* make sure it doesn't trick us into further unpleasantness. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03NFSv4: Fix a dentry leak on alias useBenjamin Coddington
commit d9dfd8d741683347ee159d25f5b50c346a0df557 upstream. In the case where d_add_unique() finds an appropriate alias to use it will have already incremented the reference count. An additional dget() to swap the open context's dentry is unnecessary and will leak a reference. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Fixes: 275bb307865a3 ("NFSv4: Move dentry instantiation into the NFSv4-...") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03block: fix use-after-free in dio_bio_completeMike Krinkin
commit 7ddc971f86aa0a4cee9f6886c356a052461957ae upstream. kasan reported the following error when i ran xfstest: [ 701.826854] ================================================================== [ 701.826864] BUG: KASAN: use-after-free in dio_bio_complete+0x41a/0x600 at addr ffff880080b95f94 [ 701.826870] Read of size 4 by task loop2/3874 [ 701.826879] page:ffffea000202e540 count:0 mapcount:0 mapping: (null) index:0x0 [ 701.826890] flags: 0x100000000000000() [ 701.826895] page dumped because: kasan: bad access detected [ 701.826904] CPU: 3 PID: 3874 Comm: loop2 Tainted: G B W L 4.5.0-rc1-next-20160129 #83 [ 701.826910] Hardware name: LENOVO 23205NG/23205NG, BIOS G2ET95WW (2.55 ) 07/09/2013 [ 701.826917] ffff88008fadf800 ffff88008fadf758 ffffffff81ca67bb 0000000041b58ab3 [ 701.826941] ffffffff830d1e74 ffffffff81ca6724 ffff88008fadf748 ffffffff8161c05c [ 701.826963] 0000000000000282 ffff88008fadf800 ffffed0010172bf2 ffffea000202e540 [ 701.826987] Call Trace: [ 701.826997] [<ffffffff81ca67bb>] dump_stack+0x97/0xdc [ 701.827005] [<ffffffff81ca6724>] ? _atomic_dec_and_lock+0xc4/0xc4 [ 701.827014] [<ffffffff8161c05c>] ? __dump_page+0x32c/0x490 [ 701.827023] [<ffffffff816b0d03>] kasan_report_error+0x5f3/0x8b0 [ 701.827033] [<ffffffff817c302a>] ? dio_bio_complete+0x41a/0x600 [ 701.827040] [<ffffffff816b1119>] __asan_report_load4_noabort+0x59/0x80 [ 701.827048] [<ffffffff817c302a>] ? dio_bio_complete+0x41a/0x600 [ 701.827053] [<ffffffff817c302a>] dio_bio_complete+0x41a/0x600 [ 701.827057] [<ffffffff81bd19c8>] ? blk_queue_exit+0x108/0x270 [ 701.827060] [<ffffffff817c32b0>] dio_bio_end_aio+0xa0/0x4d0 [ 701.827063] [<ffffffff817c3210>] ? dio_bio_complete+0x600/0x600 [ 701.827067] [<ffffffff81bd2806>] ? blk_account_io_completion+0x316/0x5d0 [ 701.827070] [<ffffffff81bafe89>] bio_endio+0x79/0x200 [ 701.827074] [<ffffffff81bd2c9f>] blk_update_request+0x1df/0xc50 [ 701.827078] [<ffffffff81c02c27>] blk_mq_end_request+0x57/0x120 [ 701.827081] [<ffffffff81c03670>] __blk_mq_complete_request+0x310/0x590 [ 701.827084] [<ffffffff812348d8>] ? set_next_entity+0x2f8/0x2ed0 [ 701.827088] [<ffffffff8124b34d>] ? put_prev_entity+0x22d/0x2a70 [ 701.827091] [<ffffffff81c0394b>] blk_mq_complete_request+0x5b/0x80 [ 701.827094] [<ffffffff821e2a33>] loop_queue_work+0x273/0x19d0 [ 701.827098] [<ffffffff811f6578>] ? finish_task_switch+0x1c8/0x8e0 [ 701.827101] [<ffffffff8129d058>] ? trace_hardirqs_on_caller+0x18/0x6c0 [ 701.827104] [<ffffffff821e27c0>] ? lo_read_simple+0x890/0x890 [ 701.827108] [<ffffffff8129dd60>] ? debug_check_no_locks_freed+0x350/0x350 [ 701.827111] [<ffffffff811f63b0>] ? __hrtick_start+0x130/0x130 [ 701.827115] [<ffffffff82a0c8f6>] ? __schedule+0x936/0x20b0 [ 701.827118] [<ffffffff811dd6bd>] ? kthread_worker_fn+0x3ed/0x8d0 [ 701.827121] [<ffffffff811dd4ed>] ? kthread_worker_fn+0x21d/0x8d0 [ 701.827125] [<ffffffff8129d058>] ? trace_hardirqs_on_caller+0x18/0x6c0 [ 701.827128] [<ffffffff811dd57f>] kthread_worker_fn+0x2af/0x8d0 [ 701.827132] [<ffffffff811dd2d0>] ? __init_kthread_worker+0x170/0x170 [ 701.827135] [<ffffffff82a1ea46>] ? _raw_spin_unlock_irqrestore+0x36/0x60 [ 701.827138] [<ffffffff811dd2d0>] ? __init_kthread_worker+0x170/0x170 [ 701.827141] [<ffffffff811dd2d0>] ? __init_kthread_worker+0x170/0x170 [ 701.827144] [<ffffffff811dd00b>] kthread+0x24b/0x3a0 [ 701.827148] [<ffffffff811dcdc0>] ? kthread_create_on_node+0x4c0/0x4c0 [ 701.827151] [<ffffffff8129d70d>] ? trace_hardirqs_on+0xd/0x10 [ 701.827155] [<ffffffff8116d41d>] ? do_group_exit+0xdd/0x350 [ 701.827158] [<ffffffff811dcdc0>] ? kthread_create_on_node+0x4c0/0x4c0 [ 701.827161] [<ffffffff82a1f52f>] ret_from_fork+0x3f/0x70 [ 701.827165] [<ffffffff811dcdc0>] ? kthread_create_on_node+0x4c0/0x4c0 [ 701.827167] Memory state around the buggy address: [ 701.827170] ffff880080b95e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 701.827172] ffff880080b95f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 701.827175] >ffff880080b95f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 701.827177] ^ [ 701.827179] ffff880080b96000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 701.827182] ffff880080b96080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 701.827183] ================================================================== The problem is that bio_check_pages_dirty calls bio_put, so we must not access bio fields after bio_check_pages_dirty. Fixes: 9b81c842355ac96097ba ("block: don't access bio->bi_error after bio_put()"). Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03writeback: keep superblock pinned during cgroup writeback association switchesTejun Heo
commit 5ff8eaac1636bf6deae86491f4818c4c69d1a9ac upstream. If cgroup writeback is in use, an inode is associated with a cgroup for writeback. If the inode's main dirtier changes to another cgroup, the association gets updated asynchronously. Nothing was pinning the superblock while such switches are in progress and superblock could go away while async switching is pending or in progress leading to crashes like the following. kernel BUG at fs/jbd2/transaction.c:319! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 1 PID: 29158 Comm: kworker/1:10 Not tainted 4.5.0-rc3 #51 Hardware name: Google Google, BIOS Google 01/01/2011 Workqueue: events inode_switch_wbs_work_fn task: ffff880213dbbd40 ti: ffff880209264000 task.ti: ffff880209264000 RIP: 0010:[<ffffffff803e6922>] [<ffffffff803e6922>] start_this_handle+0x382/0x3e0 RSP: 0018:ffff880209267c30 EFLAGS: 00010202 ... Call Trace: [<ffffffff803e6be4>] jbd2__journal_start+0xf4/0x190 [<ffffffff803cfc7e>] __ext4_journal_start_sb+0x4e/0x70 [<ffffffff803b31ec>] ext4_evict_inode+0x12c/0x3d0 [<ffffffff8035338b>] evict+0xbb/0x190 [<ffffffff80354190>] iput+0x130/0x190 [<ffffffff80360223>] inode_switch_wbs_work_fn+0x343/0x4c0 [<ffffffff80279819>] process_one_work+0x129/0x300 [<ffffffff80279b16>] worker_thread+0x126/0x480 [<ffffffff8027ed14>] kthread+0xc4/0xe0 [<ffffffff809771df>] ret_from_fork+0x3f/0x70 Fix it by bumping s_active while cgroup association switching is in flight. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Tahsin Erdogan <tahsin@google.com> Link: http://lkml.kernel.org/g/CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching") Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03namei: ->d_inode of a pinned dentry is stable only for positivesAl Viro
commit d4565649b6d6923369112758212b851adc407f0c upstream. both do_last() and walk_component() risk picking a NULL inode out of dentry about to become positive, *then* checking its flags and seeing that it's not negative anymore and using (already stale by then) value they'd fetched earlier. Usually ends up oopsing soon after that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03locks: fix unlock when fcntl_setlk races with a closeJeff Layton
commit 7f3697e24dc3820b10f445a4a7d914fc356012d1 upstream. Dmitry reported that he was able to reproduce the WARN_ON_ONCE that fires in locks_free_lock_context when the flc_posix list isn't empty. The problem turns out to be that we're basically rebuilding the file_lock from scratch in fcntl_setlk when we discover that the setlk has raced with a close. If the l_whence field is SEEK_CUR or SEEK_END, then we may end up with fl_start and fl_end values that differ from when the lock was initially set, if the file position or length of the file has changed in the interim. Fix this by just reusing the same lock request structure, and simply override fl_type value with F_UNLCK as appropriate. That ensures that we really are unlocking the lock that was initially set. While we're there, make sure that we do pop a WARN_ON_ONCE if the removal ever fails. Also return -EBADF in this event, since that's what we would have returned if the close had happened earlier. Cc: Alexander Viro <viro@zeniv.linux.org.uk> Fixes: c293621bbf67 (stale POSIX lock handling) Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03uml: fix hostfs mknod()Vegard Nossum
commit 9f2dfda2f2f1c6181c3732c16b85c59ab2d195e0 upstream. An inverted return value check in hostfs_mknod() caused the function to return success after handling it as an error (and cleaning up). It resulted in the following segfault when trying to bind() a named unix socket: Pid: 198, comm: a.out Not tainted 4.4.0-rc4 RIP: 0033:[<0000000061077df6>] RSP: 00000000daae5d60 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000006092a460 RCX: 00000000dfc54208 RDX: 0000000061073ef1 RSI: 0000000000000070 RDI: 00000000e027d600 RBP: 00000000daae5de0 R08: 00000000da980ac0 R09: 0000000000000000 R10: 0000000000000003 R11: 00007fb1ae08f72a R12: 0000000000000000 R13: 000000006092a460 R14: 00000000daaa97c0 R15: 00000000daaa9a88 Kernel panic - not syncing: Kernel mode fault at addr 0x40, ip 0x61077df6 CPU: 0 PID: 198 Comm: a.out Not tainted 4.4.0-rc4 #1 Stack: e027d620 dfc54208 0000006f da981398 61bee000 0000c1ed daae5de0 0000006e e027d620 dfcd4208 00000005 6092a460 Call Trace: [<60dedc67>] SyS_bind+0xf7/0x110 [<600587be>] handle_syscall+0x7e/0x80 [<60066ad7>] userspace+0x3e7/0x4e0 [<6006321f>] ? save_registers+0x1f/0x40 [<6006c88e>] ? arch_prctl+0x1be/0x1f0 [<60054985>] fork_handler+0x85/0x90 Let's also get rid of the "cosmic ray protection" while we're at it. Fixes: e9193059b1b3 "hostfs: fix races in dentry_name() and inode_name()" Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03btrfs: initialize the seq counter in struct btrfs_deviceSebastian Andrzej Siewior
commit 546bed631203344611f42b2af1d224d2eedb4e6b upstream. I managed to trigger this: | INFO: trying to register non-static key. | the code is fine but needs lockdep annotation. | turning off the locking correctness validator. | CPU: 1 PID: 781 Comm: systemd-gpt-aut Not tainted 4.4.0-rt2+ #14 | Hardware name: ARM-Versatile Express | [<80307cec>] (dump_stack) | [<80070e98>] (__lock_acquire) | [<8007184c>] (lock_acquire) | [<80287800>] (btrfs_ioctl) | [<8012a8d4>] (do_vfs_ioctl) | [<8012ac14>] (SyS_ioctl) so I think that btrfs_device_data_ordered_init() is not invoked behind a macro somewhere. Fixes: 7cc8e58d53cd ("Btrfs: fix unprotected device's variants on 32bits machine") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: Initialize btrfs_root->highest_objectid when loading tree root and ↵Chandan Rajendra
subvolume roots commit f32e48e925964c4f8ab917850788a87e1cef3bad upstream. The following call trace is seen when btrfs/031 test is executed in a loop, [ 158.661848] ------------[ cut here ]------------ [ 158.662634] WARNING: CPU: 2 PID: 890 at /home/chandan/repos/linux/fs/btrfs/ioctl.c:558 create_subvol+0x3d1/0x6ea() [ 158.664102] BTRFS: Transaction aborted (error -2) [ 158.664774] Modules linked in: [ 158.665266] CPU: 2 PID: 890 Comm: btrfs Not tainted 4.4.0-rc6-g511711a #2 [ 158.666251] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 158.667392] ffffffff81c0a6b0 ffff8806c7c4f8e8 ffffffff81431fc8 ffff8806c7c4f930 [ 158.668515] ffff8806c7c4f920 ffffffff81051aa1 ffff880c85aff000 ffff8800bb44d000 [ 158.669647] ffff8808863b5c98 0000000000000000 00000000fffffffe ffff8806c7c4f980 [ 158.670769] Call Trace: [ 158.671153] [<ffffffff81431fc8>] dump_stack+0x44/0x5c [ 158.671884] [<ffffffff81051aa1>] warn_slowpath_common+0x81/0xc0 [ 158.672769] [<ffffffff81051b27>] warn_slowpath_fmt+0x47/0x50 [ 158.673620] [<ffffffff813bc98d>] create_subvol+0x3d1/0x6ea [ 158.674440] [<ffffffff813777c9>] btrfs_mksubvol.isra.30+0x369/0x520 [ 158.675376] [<ffffffff8108a4aa>] ? percpu_down_read+0x1a/0x50 [ 158.676235] [<ffffffff81377a81>] btrfs_ioctl_snap_create_transid+0x101/0x180 [ 158.677268] [<ffffffff81377b52>] btrfs_ioctl_snap_create+0x52/0x70 [ 158.678183] [<ffffffff8137afb4>] btrfs_ioctl+0x474/0x2f90 [ 158.678975] [<ffffffff81144b8e>] ? vma_merge+0xee/0x300 [ 158.679751] [<ffffffff8115be31>] ? alloc_pages_vma+0x91/0x170 [ 158.680599] [<ffffffff81123f62>] ? lru_cache_add_active_or_unevictable+0x22/0x70 [ 158.681686] [<ffffffff813d99cf>] ? selinux_file_ioctl+0xff/0x1d0 [ 158.682581] [<ffffffff8117b791>] do_vfs_ioctl+0x2c1/0x490 [ 158.683399] [<ffffffff813d3cde>] ? security_file_ioctl+0x3e/0x60 [ 158.684297] [<ffffffff8117b9d4>] SyS_ioctl+0x74/0x80 [ 158.685051] [<ffffffff819b2bd7>] entry_SYSCALL_64_fastpath+0x12/0x6a [ 158.685958] ---[ end trace 4b63312de5a2cb76 ]--- [ 158.686647] BTRFS: error (device loop0) in create_subvol:558: errno=-2 No such entry [ 158.709508] BTRFS info (device loop0): forced readonly [ 158.737113] BTRFS info (device loop0): disk space caching is enabled [ 158.738096] BTRFS error (device loop0): Remounting read-write after error is not allowed [ 158.851303] BTRFS error (device loop0): cleaner transaction attach returned -30 This occurs because, Mount filesystem Create subvol with ID 257 Unmount filesystem Mount filesystem Delete subvol with ID 257 btrfs_drop_snapshot() Add root corresponding to subvol 257 into btrfs_transaction->dropped_roots list Create new subvol (i.e. create_subvol()) 257 is returned as the next free objectid btrfs_read_fs_root_no_name() Finds the btrfs_root instance corresponding to the old subvol with ID 257 in btrfs_fs_info->fs_roots_radix. Returns error since btrfs_root_item->refs has the value of 0. To fix the issue the commit initializes tree root's and subvolume root's highest_objectid when loading the roots from disk. Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: fix transaction handle leak on failure to create hard linkFilipe Manana
commit 271dba4521aed0c37c063548f876b49f5cd64b2e upstream. If we failed to create a hard link we were not always releasing the the transaction handle we got before, resulting in a memory leak and preventing any other tasks from being able to commit the current transaction. Fix this by always releasing our transaction handle. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: fix number of transaction units required to create symlinkFilipe Manana
commit 9269d12b2d57d9e3d13036bb750762d1110d425c upstream. We weren't accounting for the insertion of an inline extent item for the symlink inode nor that we need to update the parent inode item (through the call to btrfs_add_nondir()). So fix this by including two more transaction units. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: send, don't BUG_ON() when an empty symlink is foundFilipe Manana
commit a879719b8c90e15c9e7fa7266d5e3c0ca962f9df upstream. When a symlink is successfully created it always has an inline extent containing the source path. However if an error happens when creating the symlink, we can leave in the subvolume's tree a symlink inode without any such inline extent item - this happens if after btrfs_symlink() calls btrfs_end_transaction() and before it calls the inode eviction handler (through the final iput() call), the transaction gets committed and a crash happens before the eviction handler gets called, or if a snapshot of the subvolume is made before the eviction handler gets called. Sadly we can't just avoid this by making btrfs_symlink() call btrfs_end_transaction() after it calls the eviction handler, because the later can commit the current transaction before it removes any items from the subvolume tree (if it encounters ENOSPC errors while reserving space for removing all the items). So make send fail more gracefully, with an -EIO error, and print a message to dmesg/syslog informing that there's an empty symlink inode, so that the user can delete the empty symlink or do something else about it. Reported-by: Stephen R. van den Berg <srb@cuci.nl> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03btrfs: statfs: report zero available if metadata are exhaustedDavid Sterba
commit ca8a51b3a979d57b082b14eda38602b7f52d81d1 upstream. There is one ENOSPC case that's very confusing. There's Available greater than zero but no file operation succeds (besides removing files). This happens when the metadata are exhausted and there's no possibility to allocate another chunk. In this scenario it's normal that there's still some space in the data chunk and the calculation in df reflects that in the Avail value. To at least give some clue about the ENOSPC situation, let statfs report zero value in Avail, even if there's still data space available. Current: /dev/sdb1 4.0G 3.3G 719M 83% /mnt/test New: /dev/sdb1 4.0G 3.3G 0 100% /mnt/test We calculate the remaining metadata space minus global reserve. If this is (supposedly) smaller than zero, there's no space. But this does not hold in practice, the exhausted state happens where's still some positive delta. So we apply some guesswork and compare the delta to a 4M threshold. (Practically observed delta was 2M.) We probably cannot calculate the exact threshold value because this depends on the internal reservations requested by various operations, so some operations that consume a few metadata will succeed even if the Avail is zero. But this is better than the other way around. Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: igrab inode in writepageJosef Bacik
commit be7bd730841e69fe8f70120098596f648cd1f3ff upstream. We hit this panic on a few of our boxes this week where we have an ordered_extent with an NULL inode. We do an igrab() of the inode in writepages, but weren't doing it in writepage which can be called directly from the VM on dirty pages. If the inode has been unlinked then we could have I_FREEING set which means igrab() would return NULL and we get this panic. Fix this by trying to igrab in btrfs_writepage, and if it returns NULL then just redirty the page and return AOP_WRITEPAGE_ACTIVATE; so the VM knows it wasn't successful. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03Btrfs: add missing brelse when superblock checksum failsAnand Jain
commit b2acdddfad13c38a1e8b927d83c3cf321f63601a upstream. Looks like oversight, call brelse() when checksum fails. Further down the code, in the non error path, we do call brelse() and so we don't see brelse() in the goto error paths. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03ocfs2: unlock inode if deleting inode from orphan failsGuozhonghua
commit a4a8481ff68a8a324a878e281bc37f18665224f7 upstream. When doing append direct io cleanup, if deleting inode fails, it goes out without unlocking inode, which will cause the inode deadlock. This issue was introduced by commit cf1776a9e834 ("ocfs2: fix a tiny race when truncate dio orohaned entry"). Signed-off-by: Guozhonghua <guozhonghua@h3c.com> Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Reviewed-by: Gang He <ghe@suse.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03efi: Make efivarfs entries immutable by defaultPeter Jones
commit ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879 upstream. "rm -rf" is bricking some peoples' laptops because of variables being used to store non-reinitializable firmware driver data that's required to POST the hardware. These are 100% bugs, and they need to be fixed, but in the mean time it shouldn't be easy to *accidentally* brick machines. We have to have delete working, and picking which variables do and don't work for deletion is quite intractable, so instead make everything immutable by default (except for a whitelist), and make tools that aren't quite so broad-spectrum unset the immutable flag. Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad versionPeter Jones
commit e0d64e6a880e64545ad7d55786aa84ab76bac475 upstream. Translate EFI's UCS-2 variable names to UTF-8 instead of just assuming all variable names fit in ASCII. Signed-off-by: Peter Jones <pjones@redhat.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03ext4: fix bh->b_state corruptionJan Kara
commit ed8ad83808f009ade97ebbf6519bc3a97fefbc0c upstream. ext4 can update bh->b_state non-atomically in _ext4_get_block() and ext4_da_get_block_prep(). Usually this is fine since bh is just a temporary storage for mapping information on stack but in some cases it can be fully living bh attached to a page. In such case non-atomic update of bh->b_state can race with an atomic update which then gets lost. Usually when we are mapping bh and thus updating bh->b_state non-atomically, nobody else touches the bh and so things work out fine but there is one case to especially worry about: ext4_finish_bio() uses BH_Uptodate_Lock on the first bh in the page to synchronize handling of PageWriteback state. So when blocksize < pagesize, we can be atomically modifying bh->b_state of a buffer that actually isn't under IO and thus can race e.g. with delalloc trying to map that buffer. The result is that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock. Fix the problem by always updating bh->b_state bits atomically. Reported-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Nikolay Borisov <kernel@kyup.com> [NB: Backported to 4.4.2] Acked-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25timerfd: Handle relative timers with CONFIG_TIME_LOW_RES properThomas Gleixner
commit b62526ed11a1fe3861ab98d40b7fdab8981d788a upstream. Helge reported that a relative timer can return a remaining time larger than the programmed relative time on parisc and other architectures which have CONFIG_TIME_LOW_RES set. This happens because we add a jiffie to the resulting expiry time to prevent short timeouts. Use the new function hrtimer_expires_remaining_adjusted() to calculate the remaining time. It takes that extra added time into account for relative timers. Reported-and-tested-by: Helge Deller <deller@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org> Cc: linux-m68k@lists.linux-m68k.org Cc: dhowells@redhat.com Link: http://lkml.kernel.org/r/20160114164159.354500742@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25xfs: log mount failures don't wait for buffers to be releasedDave Chinner
commit 85bec5460ad8e05e0a8d70fb0f6750eb719ad092 upstream. Recently I've been seeing xfs/051 fail on 1k block size filesystems. Trying to trace the events during the test lead to the problem going away, indicating that it was a race condition that lead to this ASSERT failure: XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 156 ..... [<ffffffff814e1257>] xfs_free_perag+0x87/0xb0 [<ffffffff814e21b9>] xfs_mountfs+0x4d9/0x900 [<ffffffff814e5dff>] xfs_fs_fill_super+0x3bf/0x4d0 [<ffffffff811d8800>] mount_bdev+0x180/0x1b0 [<ffffffff814e3ff5>] xfs_fs_mount+0x15/0x20 [<ffffffff811d90a8>] mount_fs+0x38/0x170 [<ffffffff811f4347>] vfs_kern_mount+0x67/0x120 [<ffffffff811f7018>] do_mount+0x218/0xd60 [<ffffffff811f7e5b>] SyS_mount+0x8b/0xd0 When I finally caught it with tracing enabled, I saw that AG 2 had an elevated reference count and a buffer was responsible for it. I tracked down the specific buffer, and found that it was missing the final reference count release that would put it back on the LRU and hence be found by xfs_wait_buftarg() calls in the log mount failure handling. The last four traces for the buffer before the assert were (trimmed for relevance) kworker/0:1-5259 xfs_buf_iodone: hold 2 lock 0 flags ASYNC kworker/0:1-5259 xfs_buf_ioerror: hold 2 lock 0 error -5 mount-7163 xfs_buf_lock_done: hold 2 lock 0 flags ASYNC mount-7163 xfs_buf_unlock: hold 2 lock 1 flags ASYNC This is an async write that is completing, so there's nobody waiting for it directly. Hence we call xfs_buf_relse() once all the processing is complete. That does: static inline void xfs_buf_relse(xfs_buf_t *bp) { xfs_buf_unlock(bp); xfs_buf_rele(bp); } Now, it's clear that mount is waiting on the buffer lock, and that it has been released by xfs_buf_relse() and gained by mount. This is expected, because at this point the mount process is in xfs_buf_delwri_submit() waiting for all the IO it submitted to complete. The mount process, however, is waiting on the lock for the buffer because it is in xfs_buf_delwri_submit(). This waits for IO completion, but it doesn't wait for the buffer reference owned by the IO to go away. The mount process collects all the completions, fails the log recovery, and the higher level code then calls xfs_wait_buftarg() to free all the remaining buffers in the filesystem. The issue is that on unlocking the buffer, the scheduler has decided that the mount process has higher priority than the the kworker thread that is running the IO completion, and so immediately switched contexts to the mount process from the semaphore unlock code, hence preventing the kworker thread from finishing the IO completion and releasing the IO reference to the buffer. Hence by the time that xfs_wait_buftarg() is run, the buffer still has an active reference and so isn't on the LRU list that the function walks to free the remaining buffers. Hence we miss that buffer and continue onwards to tear down the mount structures, at which time we get find a stray reference count on the perag structure. On a non-debug kernel, this will be ignored and the structure torn down and freed. Hence when the kworker thread is then rescheduled and the buffer released and freed, it will access a freed perag structure. The problem here is that when the log mount fails, we still need to quiesce the log to ensure that the IO workqueues have returned to idle before we run xfs_wait_buftarg(). By synchronising the workqueues, we ensure that all IO completions are fully processed, not just to the point where buffers have been unlocked. This ensures we don't end up in the situation above. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25Revert "xfs: clear PF_NOFREEZE for xfsaild kthread"Dave Chinner
commit 3e85286e75224fa3f08bdad20e78c8327742634e upstream. This reverts commit 24ba16bb3d499c49974669cd8429c3e4138ab102 as it prevents machines from suspending. This regression occurs when the xfsaild is idle on entry to suspend, and so there s no activity to wake it from it's idle sleep and hence see that it is supposed to freeze. Hence the freezer times out waiting for it and suspend is cancelled. There is no obvious fix for this short of freezing the filesystem properly, so revert this change for now. Signed-off-by: Dave Chinner <david@fromorbit.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25xfs: inode recovery readahead can race with inode buffer creationDave Chinner
commit b79f4a1c68bb99152d0785ee4ea3ab4396cdacc6 upstream. When we do inode readahead in log recovery, we do can do the readahead before we've replayed the icreate transaction that stamps the buffer with inode cores. The inode readahead verifier catches this and marks the buffer as !done to indicate that it doesn't yet contain valid inodes. In adding buffer error notification (i.e. setting b_error = -EIO at the same time as as we clear the done flag) to such a readahead verifier failure, we can then get subsequent inode recovery failing with this error: XFS (dm-0): metadata I/O error: block 0xa00060 ("xlog_recover_do..(read#2)") error 5 numblks 32 This occurs when readahead completion races with icreate item replay such as: inode readahead find buffer lock buffer submit RA io .... icreate recovery xfs_trans_get_buffer find buffer lock buffer <blocks on RA completion> ..... <ra completion> fails verifier clear XBF_DONE set bp->b_error = -EIO release and unlock buffer <icreate gains lock> icreate initialises buffer marks buffer as done adds buffer to delayed write queue releases buffer At this point, we have an initialised inode buffer that is up to date but has an -EIO state registered against it. When we finally get to recovering an inode in that buffer: inode item recovery xfs_trans_read_buffer find buffer lock buffer sees XBF_DONE is set, returns buffer sees bp->b_error is set fail log recovery! Essentially, we need xfs_trans_get_buf_map() to clear the error status of the buffer when doing a lookup. This function returns uninitialised buffers, so the buffer returned can not be in an error state and none of the code that uses this function expects b_error to be set on return. Indeed, there is an ASSERT(!bp->b_error); in the transaction case in xfs_trans_get_buf_map() that would have caught this if log recovery used transactions.... This patch firstly changes the inode readahead failure to set -EIO on the buffer, and secondly changes xfs_buf_get_map() to never return a buffer with an error state set so this first change doesn't cause unexpected log recovery failures. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correctDarrick J. Wong
commit 96f859d52bcb1c6ea6f3388d39862bf7143e2f30 upstream. Because struct xfs_agfl is 36 bytes long and has a 64-bit integer inside it, gcc will quietly round the structure size up to the nearest 64 bits -- in this case, 40 bytes. This results in the XFS_AGFL_SIZE macro returning incorrect results for v5 filesystems on 64-bit machines (118 items instead of 119). As a result, a 32-bit xfs_repair will see garbage in AGFL item 119 and complain. Therefore, tell gcc not to pad the structure so that the AGFL size calculation is correct. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ovl: setattr: check permissions before copy-upMiklos Szeredi
commit cf9a6784f7c1b5ee2b9159a1246e327c331c5697 upstream. Without this copy-up of a file can be forced, even without actually being allowed to do anything on the file. [Arnd Bergmann] include <linux/pagemap.h> for PAGE_CACHE_SIZE (used by MAX_LFS_FILESIZE definition). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ovl: root: copy attrMiklos Szeredi
commit ed06e069775ad9236087594a1c1667367e983fb5 upstream. We copy i_uid and i_gid of underlying inode into overlayfs inode. Except for the root inode. Fix this omission. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ovl: check dentry positiveness in ovl_cleanup_whiteouts()Konstantin Khlebnikov
commit 84889d49335627bc770b32787c1ef9ebad1da232 upstream. This patch fixes kernel crash at removing directory which contains whiteouts from lower layers. Cache of directory content passed as "list" contains entries from all layers, including whiteouts from lower layers. So, lookup in upper dir (moved into work at this stage) will return negative entry. Plus this cache is filled long before and we can race with external removal. Example: mkdir -p lower0/dir lower1/dir upper work overlay touch lower0/dir/a lower0/dir/b mknod lower1/dir/a c 0 0 mount -t overlay none overlay -o lowerdir=lower1:lower0,upperdir=upper,workdir=work rm -fr overlay/dir Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ovl: use a minimal buffer in ovl_copy_xattrVito Caputo
commit e4ad29fa0d224d05e08b2858e65f112fd8edd4fe upstream. Rather than always allocating the high-order XATTR_SIZE_MAX buffer which is costly and prone to failure, only allocate what is needed and realloc if necessary. Fixes https://github.com/coreos/bugs/issues/489 Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ovl: allow zero size xattrMiklos Szeredi
commit 97daf8b97ad6f913a34c82515be64dc9ac08d63e upstream. When ovl_copy_xattr() encountered a zero size xattr no more xattrs were copied and the function returned success. This is clearly not the desired behavior. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25numa: fix /proc/<pid>/numa_maps for hugetlbfs on s390Michael Holzheu
commit 5c2ff95e41c9290d16556cd02e35b25d81be8fe0 upstream. When working with hugetlbfs ptes (which are actually pmds) is not valid to directly use pte functions like pte_present() because the hardware bit layout of pmds and ptes can be different. This is the case on s390. Therefore we have to convert the hugetlbfs ptes first into a valid pte encoding with huge_ptep_get(). Currently the /proc/<pid>/numa_maps code uses hugetlbfs ptes without huge_ptep_get(). On s390 this leads to the following two problems: 1) The pte_present() function returns false (instead of true) for PROT_NONE hugetlb ptes. Therefore PROT_NONE vmas are missing completely in the "numa_maps" output. 2) The pte_dirty() function always returns false for all hugetlb ptes. Therefore these pages are reported as "mapped=xxx" instead of "dirty=xxx". Therefore use huge_ptep_get() to correctly convert the hugetlb ptes. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25fs/hugetlbfs/inode.c: fix bugs in hugetlb_vmtruncate_list()Mike Kravetz
commit 9aacdd354d197ad64685941b36d28ea20ab88757 upstream. Hillf Danton noticed bugs in the hugetlb_vmtruncate_list routine. The argument end is of type pgoff_t. It was being converted to a vaddr offset and passed to unmap_hugepage_range. However, end was also being used as an argument to the vma_interval_tree_foreach controlling loop. In addition, the conversion of end to vaddr offset was incorrect. hugetlb_vmtruncate_list is called as part of a file truncate or fallocate hole punch operation. When truncating a hugetlbfs file, this bug could prevent some pages from being unmapped. This is possible if there are multiple vmas mapping the file, and there is a sufficiently sized hole between the mappings. The size of the hole between two vmas (A,B) must be such that the starting virtual address of B is greater than (ending virtual address of A << PAGE_SHIFT). In this case, the pages in B would not be unmapped. If pages are not properly unmapped during truncate, the following BUG is hit: kernel BUG at fs/hugetlbfs/inode.c:428! In the fallocate hole punch case, this bug could prevent pages from being unmapped as in the truncate case. However, for hole punch the result is that unmapped pages will not be removed during the operation. For hole punch, it is also possible that more pages than desired will be unmapped. This unnecessary unmapping will cause page faults to reestablish the mappings on subsequent page access. Fixes: 1bfad99ab (" hugetlbfs: hugetlb_vmtruncate_list() needs to take a range")Reported-by: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25udf: Check output buffer length when converting name to CS0Andrew Gabbasov
commit bb00c898ad1ce40c4bb422a8207ae562e9aea7ae upstream. If a name contains at least some characters with Unicode values exceeding single byte, the CS0 output should have 2 bytes per character. And if other input characters have single byte Unicode values, then the single input byte is converted to 2 output bytes, and the length of output becomes larger than the length of input. And if the input name is long enough, the output length may exceed the allocated buffer length. All this means that conversion from UTF8 or NLS to CS0 requires checking of output length in order to stop when it exceeds the given output buffer size. [JK: Make code return -ENAMETOOLONG instead of silently truncating the name] Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25udf: Prevent buffer overrun with multi-byte charactersAndrew Gabbasov
commit ad402b265ecf6fa22d04043b41444cdfcdf4f52d upstream. udf_CS0toUTF8 function stops the conversion when the output buffer length reaches UDF_NAME_LEN-2, which is correct maximum name length, but, when checking, it leaves the space for a single byte only, while multi-bytes output characters can take more space, causing buffer overflow. Similar error exists in udf_CS0toNLS function, that restricts the output length to UDF_NAME_LEN, while actual maximum allowed length is UDF_NAME_LEN-2. In these cases the output can override not only the current buffer length field, causing corruption of the name buffer itself, but also following allocation structures, causing kernel crash. Adjust the output length checks in both functions to prevent buffer overruns in case of multi-bytes UTF8 or NLS characters. Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25udf: limit the maximum number of indirect extents in a rowVegard Nossum
commit b0918d9f476a8434b055e362b83fa4fd1d462c3f upstream. udf_next_aext() just follows extent pointers while extents are marked as indirect. This can loop forever for corrupted filesystem. Limit number the of indirect extents we are willing to follow in a row. [JK: Updated changelog, limit, style] Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Jan Kara <jack@suse.com> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25pNFS/flexfiles: Fix an XDR encoding bug in layoutreturnTrond Myklebust
commit 082fa37d1351a41afc491d44a1d095cb8d919aa2 upstream. We must not skip encoding the statistics, or the server will see an XDR encoding error. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25nfs: Fix race in __update_open_stateid()Andrew Elble
commit 361cad3c89070aeb37560860ea8bfc092d545adc upstream. We've seen this in a packet capture - I've intermixed what I think was going on. The fix here is to grab the so_lock sooner. 1964379 -> #1 open (for write) reply seqid=1 1964393 -> #2 open (for read) reply seqid=2 __nfs4_close(), state->n_wronly-- nfs4_state_set_mode_locked(), changes state->state = [R] state->flags is [RW] state->state is [R], state->n_wronly == 0, state->n_rdonly == 1 1964398 -> #3 open (for write) call -> because close is already running 1964399 -> downgrade (to read) call seqid=2 (close of #1) 1964402 -> #3 open (for write) reply seqid=3 __update_open_stateid() nfs_set_open_stateid_locked(), changes state->flags state->flags is [RW] state->state is [R], state->n_wronly == 0, state->n_rdonly == 1 new sequence number is exposed now via nfs4_stateid_copy() next step would be update_open_stateflags(), pending so_lock 1964403 -> downgrade reply seqid=2, fails with OLD_STATEID (close of #1) nfs4_close_prepare() gets so_lock and recalcs flags -> send close 1964405 -> downgrade (to read) call seqid=3 (close of #1 retry) __update_open_stateid() gets so_lock * update_open_stateflags() updates state->n_wronly. nfs4_state_set_mode_locked() updates state->state state->flags is [RW] state->state is [RW], state->n_wronly == 1, state->n_rdonly == 1 * should have suppressed the preceding nfs4_close_prepare() from sending open_downgrade 1964406 -> write call 1964408 -> downgrade (to read) reply seqid=4 (close of #1 retry) nfs_clear_open_stateid_locked() state->flags is [R] state->state is [RW], state->n_wronly == 1, state->n_rdonly == 1 1964409 -> write reply (fails, openmode) Signed-off-by: Andrew Elble <aweits@rit.edu> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25pNFS/flexfiles: Fix an Oopsable typo in ff_mirror_match_fh()Trond Myklebust
commit 86fb449b07b8215443a30782dca5755d5b8b0577 upstream. Jeff reports seeing an Oops in ff_layout_alloc_lseg. Turns out copy+paste has played cruel tricks on a nested loop. Reported-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25NFS: Fix attribute cache revalidationTrond Myklebust
commit ade14a7df796d4e86bd9d181193c883a57b13db0 upstream. If a NFSv4 client uses the cache_consistency_bitmask in order to request only information about the change attribute, timestamps and size, then it has not revalidated all attributes, and hence the attribute timeout timestamp should not be updated. Reported-by: Donald Buczek <buczek@molgen.mpg.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25cifs: fix erroneous return valueAnton Protopopov
commit 4b550af519854421dfec9f7732cdddeb057134b2 upstream. The setup_ntlmv2_rsp() function may return positive value ENOMEM instead of -ENOMEM in case of kmalloc failure. Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25cifs_dbg() outputs an uninitialized buffer in cifs_readdir()Vasily Averin
commit 01b9b0b28626db4a47d7f48744d70abca9914ef1 upstream. In some cases tmp_bug can be not filled in cifs_filldir and stay uninitialized, therefore its printk with "%s" modifier can leak content of kernelspace memory. If old content of this buffer does not contain '\0' access bejond end of allocated object can crash the host. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: Steve French <sfrench@localhost.localdomain> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25cifs: fix race between call_async() and reconnect()Rabin Vincent
commit 820962dc700598ffe8cd21b967e30e7520c34748 upstream. cifs_call_async() queues the MID to the pending list and calls smb_send_rqst(). If smb_send_rqst() performs a partial send, it sets the tcpStatus to CifsNeedReconnect and returns an error code to cifs_call_async(). In this case, cifs_call_async() removes the MID from the list and returns to the caller. However, cifs_call_async() releases the server mutex _before_ removing the MID. This means that a cifs_reconnect() can race with this function and manage to remove the MID from the list and delete the entry before cifs_call_async() calls cifs_delete_mid(). This leads to various crashes due to the use after free in cifs_delete_mid(). Task1 Task2 cifs_call_async(): - rc = -EAGAIN - mutex_unlock(srv_mutex) cifs_reconnect(): - mutex_lock(srv_mutex) - mutex_unlock(srv_mutex) - list_delete(mid) - mid->callback() cifs_writev_callback(): - mutex_lock(srv_mutex) - delete(mid) - mutex_unlock(srv_mutex) - cifs_delete_mid(mid) <---- use after free Fix this by removing the MID in cifs_call_async() before releasing the srv_mutex. Also hold the srv_mutex in cifs_reconnect() until the MIDs are moved out of the pending list. Signed-off-by: Rabin Vincent <rabin.vincent@axis.com> Acked-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Signed-off-by: Steve French <sfrench@localhost.localdomain> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25cifs: Ratelimit kernel log messagesJamie Bainbridge
commit ec7147a99e33a9e4abad6fc6e1b40d15df045d53 upstream. Under some conditions, CIFS can repeatedly call the cifs_dbg() logging wrapper. If done rapidly enough, the console framebuffer can softlockup or "rcu_sched self-detected stall". Apply the built-in log ratelimiters to prevent such hangs. Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25ptrace: use fsuid, fsgid, effective creds for fs access checksJann Horn
commit caaee6234d05a58c5b4d05e7bf766131b810a657 upstream. By checking the effective credentials instead of the real UID / permitted capabilities, ensure that the calling process actually intended to use its credentials. To ensure that all ptrace checks use the correct caller credentials (e.g. in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS flag), use two new flags and require one of them to be set. The problem was that when a privileged task had temporarily dropped its privileges, e.g. by calling setreuid(0, user_uid), with the intent to perform following syscalls with the credentials of a user, it still passed ptrace access checks that the user would not be able to pass. While an attacker should not be able to convince the privileged task to perform a ptrace() syscall, this is a problem because the ptrace access check is reused for things in procfs. In particular, the following somewhat interesting procfs entries only rely on ptrace access checks: /proc/$pid/stat - uses the check for determining whether pointers should be visible, useful for bypassing ASLR /proc/$pid/maps - also useful for bypassing ASLR /proc/$pid/cwd - useful for gaining access to restricted directories that contain files with lax permissions, e.g. in this scenario: lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar drwx------ root root /root drwxr-xr-x root root /root/foobar -rw-r--r-- root root /root/foobar/secret Therefore, on a system where a root-owned mode 6755 binary changes its effective credentials as described and then dumps a user-specified file, this could be used by an attacker to reveal the memory layout of root's processes or reveal the contents of files he is not allowed to access (through /proc/$pid/cwd). [akpm@linux-foundation.org: fix warning] Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Kees Cook <keescook@chromium.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25Btrfs: fix direct IO requests not reporting IO error to user spaceFilipe Manana
commit 1636d1d77ef4e01e57f706a4cae3371463896136 upstream. If a bio for a direct IO request fails, we were not setting the error in the parent bio (the main DIO bio), making us not return the error to user space in btrfs_direct_IO(), that is, it made __blockdev_direct_IO() return the number of bytes issued for IO and not the error a bio created and submitted by btrfs_submit_direct() got from the block layer. This essentially happens because when we call: dio_end_io(dio_bio, bio->bi_error); It does not set dio_bio->bi_error to the value of the second argument. So just add this missing assignment in endio callbacks, just as we do in the error path at btrfs_submit_direct() when we fail to clone the dio bio or allocate its private object. This follows the convention of what is done with other similar APIs such as bio_endio() where the caller is responsible for setting the bi_error field in the bio it passes as an argument to bio_endio(). This was detected by the new generic test cases in xfstests: 271, 272, 276 and 278. Which essentially setup a dm error target, then load the error table, do a direct IO write and unload the error table. They expect the write to fail with -EIO, which was not getting reported when testing against btrfs. Fixes: 4246a0b63bd8 ("block: add a bi_error field to struct bio") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25Btrfs: fix hang on extent buffer lock caused by the inode_paths ioctlFilipe Manana
commit 0c0fe3b0fa45082cd752553fdb3a4b42503a118e upstream. While doing some tests I ran into an hang on an extent buffer's rwlock that produced the following trace: [39389.800012] NMI watchdog: BUG: soft lockup - CPU#15 stuck for 22s! [fdm-stress:32166] [39389.800016] NMI watchdog: BUG: soft lockup - CPU#14 stuck for 22s! [fdm-stress:32165] [39389.800016] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs] [39389.800016] irq event stamp: 0 [39389.800016] hardirqs last enabled at (0): [< (null)>] (null) [39389.800016] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800016] softirqs last enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800016] softirqs last disabled at (0): [< (null)>] (null) [39389.800016] CPU: 14 PID: 32165 Comm: fdm-stress Not tainted 4.4.0-rc6-btrfs-next-18+ #1 [39389.800016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [39389.800016] task: ffff880175b1ca40 ti: ffff8800a185c000 task.ti: ffff8800a185c000 [39389.800016] RIP: 0010:[<ffffffff810902af>] [<ffffffff810902af>] queued_spin_lock_slowpath+0x57/0x158 [39389.800016] RSP: 0018:ffff8800a185fb80 EFLAGS: 00000202 [39389.800016] RAX: 0000000000000101 RBX: ffff8801710c4e9c RCX: 0000000000000101 [39389.800016] RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001 [39389.800016] RBP: ffff8800a185fb98 R08: 0000000000000001 R09: 0000000000000000 [39389.800016] R10: ffff8800a185fb68 R11: 6db6db6db6db6db7 R12: ffff8801710c4e98 [39389.800016] R13: ffff880175b1ca40 R14: ffff8800a185fc10 R15: ffff880175b1ca40 [39389.800016] FS: 00007f6d37fff700(0000) GS:ffff8802be9c0000(0000) knlGS:0000000000000000 [39389.800016] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [39389.800016] CR2: 00007f6d300019b8 CR3: 0000000037c93000 CR4: 00000000001406e0 [39389.800016] Stack: [39389.800016] ffff8801710c4e98 ffff8801710c4e98 ffff880175b1ca40 ffff8800a185fbb0 [39389.800016] ffffffff81091e11 ffff8801710c4e98 ffff8800a185fbc8 ffffffff81091895 [39389.800016] ffff8801710c4e98 ffff8800a185fbe8 ffffffff81486c5c ffffffffa067288c [39389.800016] Call Trace: [39389.800016] [<ffffffff81091e11>] queued_read_lock_slowpath+0x46/0x60 [39389.800016] [<ffffffff81091895>] do_raw_read_lock+0x3e/0x41 [39389.800016] [<ffffffff81486c5c>] _raw_read_lock+0x3d/0x44 [39389.800016] [<ffffffffa067288c>] ? btrfs_tree_read_lock+0x54/0x125 [btrfs] [39389.800016] [<ffffffffa067288c>] btrfs_tree_read_lock+0x54/0x125 [btrfs] [39389.800016] [<ffffffffa0622ced>] ? btrfs_find_item+0xa7/0xd2 [btrfs] [39389.800016] [<ffffffffa069363f>] btrfs_ref_to_path+0xd6/0x174 [btrfs] [39389.800016] [<ffffffffa0693730>] inode_to_path+0x53/0xa2 [btrfs] [39389.800016] [<ffffffffa0693e2e>] paths_from_inode+0x117/0x2ec [btrfs] [39389.800016] [<ffffffffa0670cff>] btrfs_ioctl+0xd5b/0x2793 [btrfs] [39389.800016] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800016] [<ffffffff81276727>] ? __this_cpu_preempt_check+0x13/0x15 [39389.800016] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800016] [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d [39389.800016] [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea [39389.800016] [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71 [39389.800016] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [39389.800016] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [39389.800016] Code: b9 01 01 00 00 f7 c6 00 ff ff ff 75 32 83 fe 01 89 ca 89 f0 0f 45 d7 f0 0f b1 13 39 f0 74 04 89 c6 eb e2 ff ca 0f 84 fa 00 00 00 <8b> 03 84 c0 74 04 f3 90 eb f6 66 c7 03 01 00 e9 e6 00 00 00 e8 [39389.800012] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs] [39389.800012] irq event stamp: 0 [39389.800012] hardirqs last enabled at (0): [< (null)>] (null) [39389.800012] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800012] softirqs last enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800012] softirqs last disabled at (0): [< (null)>] (null) [39389.800012] CPU: 15 PID: 32166 Comm: fdm-stress Tainted: G L 4.4.0-rc6-btrfs-next-18+ #1 [39389.800012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [39389.800012] task: ffff880179294380 ti: ffff880034a60000 task.ti: ffff880034a60000 [39389.800012] RIP: 0010:[<ffffffff81091e8d>] [<ffffffff81091e8d>] queued_write_lock_slowpath+0x62/0x72 [39389.800012] RSP: 0018:ffff880034a639f0 EFLAGS: 00000206 [39389.800012] RAX: 0000000000000101 RBX: ffff8801710c4e98 RCX: 0000000000000000 [39389.800012] RDX: 00000000000000ff RSI: 0000000000000000 RDI: ffff8801710c4e9c [39389.800012] RBP: ffff880034a639f8 R08: 0000000000000001 R09: 0000000000000000 [39389.800012] R10: ffff880034a639b0 R11: 0000000000001000 R12: ffff8801710c4e98 [39389.800012] R13: 0000000000000001 R14: ffff880172cbc000 R15: ffff8801710c4e00 [39389.800012] FS: 00007f6d377fe700(0000) GS:ffff8802be9e0000(0000) knlGS:0000000000000000 [39389.800012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [39389.800012] CR2: 00007f6d3d3c1000 CR3: 0000000037c93000 CR4: 00000000001406e0 [39389.800012] Stack: [39389.800012] ffff8801710c4e98 ffff880034a63a10 ffffffff81091963 ffff8801710c4e98 [39389.800012] ffff880034a63a30 ffffffff81486f1b ffffffffa0672cb3 ffff8801710c4e00 [39389.800012] ffff880034a63a78 ffffffffa0672cb3 ffff8801710c4e00 ffff880034a63a58 [39389.800012] Call Trace: [39389.800012] [<ffffffff81091963>] do_raw_write_lock+0x72/0x8c [39389.800012] [<ffffffff81486f1b>] _raw_write_lock+0x3a/0x41 [39389.800012] [<ffffffffa0672cb3>] ? btrfs_tree_lock+0x119/0x251 [btrfs] [39389.800012] [<ffffffffa0672cb3>] btrfs_tree_lock+0x119/0x251 [btrfs] [39389.800012] [<ffffffffa061aeba>] ? rcu_read_unlock+0x5b/0x5d [btrfs] [39389.800012] [<ffffffffa061ce13>] ? btrfs_root_node+0xda/0xe6 [btrfs] [39389.800012] [<ffffffffa061ce83>] btrfs_lock_root_node+0x22/0x42 [btrfs] [39389.800012] [<ffffffffa062046b>] btrfs_search_slot+0x1b8/0x758 [btrfs] [39389.800012] [<ffffffff810fc6b0>] ? time_hardirqs_on+0x15/0x28 [39389.800012] [<ffffffffa06365db>] btrfs_lookup_inode+0x31/0x95 [btrfs] [39389.800012] [<ffffffff8108d62f>] ? trace_hardirqs_on+0xd/0xf [39389.800012] [<ffffffff8148482b>] ? mutex_lock_nested+0x397/0x3bc [39389.800012] [<ffffffffa068821b>] __btrfs_update_delayed_inode+0x59/0x1c0 [btrfs] [39389.800012] [<ffffffffa068858e>] __btrfs_commit_inode_delayed_items+0x194/0x5aa [btrfs] [39389.800012] [<ffffffff81486ab7>] ? _raw_spin_unlock+0x31/0x44 [39389.800012] [<ffffffffa0688a48>] __btrfs_run_delayed_items+0xa4/0x15c [btrfs] [39389.800012] [<ffffffffa0688d62>] btrfs_run_delayed_items+0x11/0x13 [btrfs] [39389.800012] [<ffffffffa064048e>] btrfs_commit_transaction+0x234/0x96e [btrfs] [39389.800012] [<ffffffffa0618d10>] btrfs_sync_fs+0x145/0x1ad [btrfs] [39389.800012] [<ffffffffa0671176>] btrfs_ioctl+0x11d2/0x2793 [btrfs] [39389.800012] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800012] [<ffffffff81140261>] ? __might_fault+0x4c/0xa7 [39389.800012] [<ffffffff81140261>] ? __might_fault+0x4c/0xa7 [39389.800012] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800012] [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d [39389.800012] [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea [39389.800012] [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71 [39389.800012] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [39389.800012] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [39389.800012] Code: f0 0f b1 13 85 c0 75 ef eb 2a f3 90 8a 03 84 c0 75 f8 f0 0f b0 13 84 c0 75 f0 ba ff 00 00 00 eb 0a f0 0f b1 13 ff c8 74 0b f3 90 <8b> 03 83 f8 01 75 f7 eb ed c6 43 04 00 5b 5d c3 0f 1f 44 00 00 This happens because in the code path executed by the inode_paths ioctl we end up nesting two calls to read lock a leaf's rwlock when after the first call to read_lock() and before the second call to read_lock(), another task (running the delayed items as part of a transaction commit) has already called write_lock() against the leaf's rwlock. This situation is illustrated by the following diagram: Task A Task B btrfs_ref_to_path() btrfs_commit_transaction() read_lock(&eb->lock); btrfs_run_delayed_items() __btrfs_commit_inode_delayed_items() __btrfs_update_delayed_inode() btrfs_lookup_inode() write_lock(&eb->lock); --> task waits for lock read_lock(&eb->lock); --> makes this task hang forever (and task B too of course) So fix this by avoiding doing the nested read lock, which is easily avoidable. This issue does not happen if task B calls write_lock() after task A does the second call to read_lock(), however there does not seem to exist anything in the documentation that mentions what is the expected behaviour for recursive locking of rwlocks (leaving the idea that doing so is not a good usage of rwlocks). Also, as a side effect necessary for this fix, make sure we do not needlessly read lock extent buffers when the input path has skip_locking set (used when called from send). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25Btrfs: fix page reading in extent_same ioctl leading to csum errorsFilipe Manana
commit 313140023026ae542ad76e7e268c56a1eaa2c28e upstream. In the extent_same ioctl, we were grabbing the pages (locked) and attempting to read them without bothering about any concurrent IO against them. That is, we were not checking for any ongoing ordered extents nor waiting for them to complete, which leads to a race where the extent_same() code gets a checksum verification error when it reads the pages, producing a message like the following in dmesg and making the operation fail to user space with -ENOMEM: [18990.161265] BTRFS warning (device sdc): csum failed ino 259 off 495616 csum 685204116 expected csum 1515870868 Fix this by using btrfs_readpage() for reading the pages instead of extent_read_full_page_nolock(), which waits for any concurrent ordered extents to complete and locks the io range. Also do better error handling and don't treat all failures as -ENOMEM, as that's clearly misleasing, becoming identical to the checks and operation of prepare_uptodate_page(). The use of extent_read_full_page_nolock() was required before commit f441460202cb ("btrfs: fix deadlock with extent-same and readpage"), as we had the range locked in an inode's io tree before attempting to read the pages. Fixes: f441460202cb ("btrfs: fix deadlock with extent-same and readpage") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-25Btrfs: fix invalid page accesses in extent_same (dedup) ioctlFilipe Manana
commit e0bd70c67bf996b360f706b6c643000f2e384681 upstream. In the extent_same ioctl we are getting the pages for the source and target ranges and unlocking them immediately after, which is incorrect because later we attempt to map them (with kmap_atomic) and access their contents at btrfs_cmp_data(). When we do such access the pages might have been relocated or removed from memory, which leads to an invalid memory access. This issue is detected on a kernel with CONFIG_DEBUG_PAGEALLOC=y which produces a trace like the following: 186736.677437] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [186736.680382] Modules linked in: btrfs dm_flakey dm_mod ppdev xor raid6_pq sha256_generic hmac drbg ansi_cprng acpi_cpufreq evdev sg aesni_intel aes_x86_64 parport_pc ablk_helper tpm_tis psmouse parport i2c_piix4 tpm cryptd i2c_core lrw processor button serio_raw pcspkr gf128mul glue_helper loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs] [186736.681319] CPU: 13 PID: 10222 Comm: duperemove Tainted: G W 4.4.0-rc6-btrfs-next-18+ #1 [186736.681319] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [186736.681319] task: ffff880132600400 ti: ffff880362284000 task.ti: ffff880362284000 [186736.681319] RIP: 0010:[<ffffffff81264d00>] [<ffffffff81264d00>] memcmp+0xb/0x22 [186736.681319] RSP: 0018:ffff880362287d70 EFLAGS: 00010287 [186736.681319] RAX: 000002c002468acf RBX: 0000000012345678 RCX: 0000000000000000 [186736.681319] RDX: 0000000000001000 RSI: 0005d129c5cf9000 RDI: 0005d129c5cf9000 [186736.681319] RBP: ffff880362287d70 R08: 0000000000000000 R09: 0000000000001000 [186736.681319] R10: ffff880000000000 R11: 0000000000000476 R12: 0000000000001000 [186736.681319] R13: ffff8802f91d4c88 R14: ffff8801f2a77830 R15: ffff880352e83e40 [186736.681319] FS: 00007f27b37fe700(0000) GS:ffff88043dda0000(0000) knlGS:0000000000000000 [186736.681319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [186736.681319] CR2: 00007f27a406a000 CR3: 0000000217421000 CR4: 00000000001406e0 [186736.681319] Stack: [186736.681319] ffff880362287ea0 ffffffffa048d0bd 000000000009f000 0000000000001000 [186736.681319] 0100000000000000 ffff8801f2a77850 ffff8802f91d49b0 ffff880132600400 [186736.681319] 00000000000004f8 ffff8801c1efbe41 0000000000000000 0000000000000038 [186736.681319] Call Trace: [186736.681319] [<ffffffffa048d0bd>] btrfs_ioctl+0x24cb/0x2731 [btrfs] [186736.681319] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [186736.681319] [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d [186736.681319] [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea [186736.681319] [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71 [186736.681319] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [186736.681319] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [186736.681319] Code: 0a 3c 6e 74 0d 3c 79 74 04 3c 59 75 0c c6 06 01 eb 03 c6 06 00 31 c0 eb 05 b8 ea ff ff ff 5d c3 55 31 c9 48 89 e5 48 39 d1 74 13 <0f> b6 04 0f 44 0f b6 04 0e 48 ff c1 44 29 c0 74 ea eb 02 31 c0 (gdb) list *(btrfs_ioctl+0x24cb) 0x5e0e1 is in btrfs_ioctl (fs/btrfs/ioctl.c:2972). 2967 dst_addr = kmap_atomic(dst_page); 2968 2969 flush_dcache_page(src_page); 2970 flush_dcache_page(dst_page); 2971 2972 if (memcmp(addr, dst_addr, cmp_len)) 2973 ret = BTRFS_SAME_DATA_DIFFERS; 2974 2975 kunmap_atomic(addr); 2976 kunmap_atomic(dst_addr); So fix this by making sure we keep the pages locked and respect the same locking order as everywhere else: get and lock the pages first and then lock the range in the inode's io tree (like for example at __btrfs_buffered_write() and extent_readpages()). If an ordered extent is found after locking the range in the io tree, unlock the range, unlock the pages, wait for the ordered extent to complete and repeat the entire locking process until no overlapping ordered extents are found. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>