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2017-01-09sg_write()/bsg_write() is not fit to be called under KERNEL_DSAl Viro
commit 128394eff343fc6d2f32172f03e24829539c5835 upstream. Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-06blk-mq: Do not invoke .queue_rq() for a stopped queueBart Van Assche
commit bc27c01b5c46d3bfec42c96537c7a3fae0bb2cc4 upstream. The meaning of the BLK_MQ_S_STOPPED flag is "do not call .queue_rq()". Hence modify blk_mq_make_request() such that requests are queued instead of issued if a queue has been stopped. Reported-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-10Don't feed anything but regular iovec's to blk_rq_map_user_iovLinus Torvalds
commit a0ac402cfcdc904f9772e1762b3fda112dcc56a0 upstream. In theory we could map other things, but there's a reason that function is called "user_iov". Using anything else (like splice can do) just confuses it. Reported-and-tested-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-28blkcg: Unlock blkcg_pol_mutex only once when cpd == NULLBart Van Assche
commit bbb427e342495df1cda10051d0566388697499c0 upstream. Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register() such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch avoids that smatch reports the following error: block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex' Fixes: 06b285bd1125 ("blkcg: fix blkcg_policy_data allocation bug") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-22cfq: fix starvation of asynchronous writesGlauber Costa
commit 3932a86b4b9d1f0b049d64d4591ce58ad18b44ec upstream. While debugging timeouts happening in my application workload (ScyllaDB), I have observed calls to open() taking a long time, ranging everywhere from 2 seconds - the first ones that are enough to time out my application - to more than 30 seconds. The problem seems to happen because XFS may block on pending metadata updates under certain circumnstances, and that's confirmed with the following backtrace taken by the offcputime tool (iovisor/bcc): ffffffffb90c57b1 finish_task_switch ffffffffb97dffb5 schedule ffffffffb97e310c schedule_timeout ffffffffb97e1f12 __down ffffffffb90ea821 down ffffffffc046a9dc xfs_buf_lock ffffffffc046abfb _xfs_buf_find ffffffffc046ae4a xfs_buf_get_map ffffffffc046babd xfs_buf_read_map ffffffffc0499931 xfs_trans_read_buf_map ffffffffc044a561 xfs_da_read_buf ffffffffc0451390 xfs_dir3_leaf_read.constprop.16 ffffffffc0452b90 xfs_dir2_leaf_lookup_int ffffffffc0452e0f xfs_dir2_leaf_lookup ffffffffc044d9d3 xfs_dir_lookup ffffffffc047d1d9 xfs_lookup ffffffffc0479e53 xfs_vn_lookup ffffffffb925347a path_openat ffffffffb9254a71 do_filp_open ffffffffb9242a94 do_sys_open ffffffffb9242b9e sys_open ffffffffb97e42b2 entry_SYSCALL_64_fastpath 00007fb0698162ed [unknown] Inspecting my run with blktrace, I can see that the xfsaild kthread exhibit very high "Dispatch wait" times, on the dozens of seconds range and consistent with the open() times I have saw in that run. Still from the blktrace output, we can after searching a bit, identify the request that wasn't dispatched: 8,0 11 152 81.092472813 804 A WM 141698288 + 8 <- (8,1) 141696240 8,0 11 153 81.092472889 804 Q WM 141698288 + 8 [xfsaild/sda1] 8,0 11 154 81.092473207 804 G WM 141698288 + 8 [xfsaild/sda1] 8,0 11 206 81.092496118 804 I WM 141698288 + 8 ( 22911) [xfsaild/sda1] <==== 'I' means Inserted (into the IO scheduler) ===================================> 8,0 0 289372 96.718761435 0 D WM 141698288 + 8 (15626265317) [swapper/0] <==== Only 15s later the CFQ scheduler dispatches the request ======================> As we can see above, in this particular example CFQ took 15 seconds to dispatch this request. Going back to the full trace, we can see that the xfsaild queue had plenty of opportunity to run, and it was selected as the active queue many times. It would just always be preempted by something else (example): 8,0 1 0 81.117912979 0 m N cfq1618SN / insert_request 8,0 1 0 81.117913419 0 m N cfq1618SN / add_to_rr 8,0 1 0 81.117914044 0 m N cfq1618SN / preempt 8,0 1 0 81.117914398 0 m N cfq767A / slice expired t=1 8,0 1 0 81.117914755 0 m N cfq767A / resid=40 8,0 1 0 81.117915340 0 m N / served: vt=1948520448 min_vt=1948520448 8,0 1 0 81.117915858 0 m N cfq767A / sl_used=1 disp=0 charge=0 iops=1 sect=0 where cfq767 is the xfsaild queue and cfq1618 corresponds to one of the ScyllaDB IO dispatchers. The requests preempting the xfsaild queue are synchronous requests. That's a characteristic of ScyllaDB workloads, as we only ever issue O_DIRECT requests. While it can be argued that preempting ASYNC requests in favor of SYNC is part of the CFQ logic, I don't believe that doing so for 15+ seconds is anyone's goal. Moreover, unless I am misunderstanding something, that breaks the expectation set by the "fifo_expire_async" tunable, which in my system is set to the default. Looking at the code, it seems to me that the issue is that after we make an async queue active, there is no guarantee that it will execute any request. When the queue itself tests if it cfq_may_dispatch() it can bail if it sees SYNC requests in flight. An incoming request from another queue can also preempt it in such situation before we have the chance to execute anything (as seen in the trace above). This patch sets the must_dispatch flag if we notice that we have requests that are already fifo_expired. This flag is always cleared after cfq_dispatch_request() returns from cfq_dispatch_requests(), so it won't pin the queue for subsequent requests (unless they are themselves expired) Care is taken during preempt to still allow rt requests to preempt us regardless. Testing my workload with this patch applied produces much better results. From the application side I see no timeouts, and the open() latency histogram generated by systemtap looks much better, with the worst outlier at 131ms: Latency histogram of xfs_buf_lock acquisition (microseconds): value |-------------------------------------------------- count 0 | 11 1 |@@@@ 161 2 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1966 4 |@ 54 8 | 36 16 | 7 32 | 0 64 | 0 ~ 1024 | 0 2048 | 0 4096 | 1 8192 | 1 16384 | 2 32768 | 0 65536 | 0 131072 | 1 262144 | 0 524288 | 0 Signed-off-by: Glauber Costa <glauber@scylladb.com> CC: Jens Axboe <axboe@kernel.dk> CC: linux-block@vger.kernel.org CC: linux-kernel@vger.kernel.org Signed-off-by: Glauber Costa <glauber@scylladb.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-07blk-mq: actually hook up defer list when running requestsOmar Sandoval
commit 52b9c330c6a8a4b5a1819bdaddf4ec76ab571e81 upstream. If ->queue_rq() returns BLK_MQ_RQ_QUEUE_OK, we use continue and skip over the rest of the loop body. However, dptr is assigned later in the loop body, and the BLK_MQ_RQ_QUEUE_OK case is exactly the case that we'd want it for. NVMe isn't actually using BLK_MQ_F_DEFER_ISSUE yet, nor is any other in-tree driver, but if the code's going to be there, it might as well work. Fixes: 74c450521dd8 ("blk-mq: add a 'list' parameter to ->queue_rq()") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-15block: make sure a big bio is split into at most 256 bvecsMing Lei
commit 4d70dca4eadf2f95abe389116ac02b8439c2d16c upstream. After arbitrary bio size was introduced, the incoming bio may be very big. We have to split the bio into small bios so that each holds at most BIO_MAX_PAGES bvecs for safety reason, such as bio_clone(). This patch fixes the following kernel crash: > [ 172.660142] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 > [ 172.660229] IP: [<ffffffff811e53b4>] bio_trim+0xf/0x2a > [ 172.660289] PGD 7faf3e067 PUD 7f9279067 PMD 0 > [ 172.660399] Oops: 0000 [#1] SMP > [...] > [ 172.664780] Call Trace: > [ 172.664813] [<ffffffffa007f3be>] ? raid1_make_request+0x2e8/0xad7 [raid1] > [ 172.664846] [<ffffffff811f07da>] ? blk_queue_split+0x377/0x3d4 > [ 172.664880] [<ffffffffa005fb5f>] ? md_make_request+0xf6/0x1e9 [md_mod] > [ 172.664912] [<ffffffff811eb860>] ? generic_make_request+0xb5/0x155 > [ 172.664947] [<ffffffffa0445c89>] ? prio_io+0x85/0x95 [bcache] > [ 172.664981] [<ffffffffa0448252>] ? register_cache_set+0x355/0x8d0 [bcache] > [ 172.665016] [<ffffffffa04497d3>] ? register_bcache+0x1006/0x1174 [bcache] The issue can be reproduced by the following steps: - create one raid1 over two virtio-blk - build bcache device over the above raid1 and another cache device and bucket size is set as 2Mbytes - set cache mode as writeback - run random write over ext4 on the bcache device Fixes: 54efd50(block: make generic_make_request handle arbitrarily sized bios) Reported-by: Sebastian Roesner <sroesner-kernelorg@roesner-online.de> Reported-by: Eric Wheeler <bcache@lists.ewheeler.net> Cc: Shaohua Li <shli@fb.com> Acked-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-15block: Fix race triggered by blk_set_queue_dying()Bart Van Assche
commit 1b856086813be9371929b6cc62045f9fd470f5a0 upstream. blk_set_queue_dying() can be called while another thread is submitting I/O or changing queue flags, e.g. through dm_stop_queue(). Hence protect the QUEUE_FLAG_DYING flag change with locking. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-15blk-mq: End unstarted requests on dying queueKeith Busch
[ Upstream commit a59e0f5795fe52dad42a99c00287e3766153b312 ] Go directly to ending a request if it wasn't started. Previously, completing a request may invoke a driver callback for a request it didn't initialize. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-20block: fix bdi vs gendisk lifetime mismatchDan Williams
commit df08c32ce3be5be138c1dbfcba203314a3a7cd6f upstream. The name for a bdi of a gendisk is derived from the gendisk's devt. However, since the gendisk is destroyed before the bdi it leaves a window where a new gendisk could dynamically reuse the same devt while a bdi with the same name is still live. Arrange for the bdi to hold a reference against its "owner" disk device while it is registered. Otherwise we can hit sysfs duplicate name collisions like the following: WARNING: CPU: 10 PID: 2078 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x80 sysfs: cannot create duplicate filename '/devices/virtual/bdi/259:1' Hardware name: HP ProLiant DL580 Gen8, BIOS P79 05/06/2015 0000000000000286 0000000002c04ad5 ffff88006f24f970 ffffffff8134caec ffff88006f24f9c0 0000000000000000 ffff88006f24f9b0 ffffffff8108c351 0000001f0000000c ffff88105d236000 ffff88105d1031e0 ffff8800357427f8 Call Trace: [<ffffffff8134caec>] dump_stack+0x63/0x87 [<ffffffff8108c351>] __warn+0xd1/0xf0 [<ffffffff8108c3cf>] warn_slowpath_fmt+0x5f/0x80 [<ffffffff812a0d34>] sysfs_warn_dup+0x64/0x80 [<ffffffff812a0e1e>] sysfs_create_dir_ns+0x7e/0x90 [<ffffffff8134faaa>] kobject_add_internal+0xaa/0x320 [<ffffffff81358d4e>] ? vsnprintf+0x34e/0x4d0 [<ffffffff8134ff55>] kobject_add+0x75/0xd0 [<ffffffff816e66b2>] ? mutex_lock+0x12/0x2f [<ffffffff8148b0a5>] device_add+0x125/0x610 [<ffffffff8148b788>] device_create_groups_vargs+0xd8/0x100 [<ffffffff8148b7cc>] device_create_vargs+0x1c/0x20 [<ffffffff811b775c>] bdi_register+0x8c/0x180 [<ffffffff811b7877>] bdi_register_dev+0x27/0x30 [<ffffffff813317f5>] add_disk+0x175/0x4a0 Reported-by: Yi Zhang <yizhan@redhat.com> Tested-by: Yi Zhang <yizhan@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixed up missing 0 return in bdi_register_owner(). Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-20block: add missing group association in bio-cloning functionsPaolo Valente
commit 20bd723ec6a3261df5e02250cd3a1fbb09a343f2 upstream. When a bio is cloned, the newly created bio must be associated with the same blkcg as the original bio (if BLK_CGROUP is enabled). If this operation is not performed, then the new bio is not associated with any group, and the group of the current task is returned when the group of the bio is requested. Depending on the cloning frequency, this may cause a large percentage of the bios belonging to a given group to be treated as if belonging to other groups (in most cases as if belonging to the root group). The expected group isolation may thereby be broken. This commit adds the missing association in bio-cloning functions. Fixes: da2f0f74cf7d ("Btrfs: add support for blkio controllers") Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Reviewed-by: Nikolay Borisov <kernel@kyup.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-16block: fix use-after-free in seq fileVegard Nossum
commit 77da160530dd1dc94f6ae15a981f24e5f0021e84 upstream. I got a KASAN report of use-after-free: ================================================================== BUG: KASAN: use-after-free in klist_iter_exit+0x61/0x70 at addr ffff8800b6581508 Read of size 8 by task trinity-c1/315 ============================================================================= BUG kmalloc-32 (Not tainted): kasan: bad access detected ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in disk_seqf_start+0x66/0x110 age=144 cpu=1 pid=315 ___slab_alloc+0x4f1/0x520 __slab_alloc.isra.58+0x56/0x80 kmem_cache_alloc_trace+0x260/0x2a0 disk_seqf_start+0x66/0x110 traverse+0x176/0x860 seq_read+0x7e3/0x11a0 proc_reg_read+0xbc/0x180 do_loop_readv_writev+0x134/0x210 do_readv_writev+0x565/0x660 vfs_readv+0x67/0xa0 do_preadv+0x126/0x170 SyS_preadv+0xc/0x10 do_syscall_64+0x1a1/0x460 return_from_SYSCALL_64+0x0/0x6a INFO: Freed in disk_seqf_stop+0x42/0x50 age=160 cpu=1 pid=315 __slab_free+0x17a/0x2c0 kfree+0x20a/0x220 disk_seqf_stop+0x42/0x50 traverse+0x3b5/0x860 seq_read+0x7e3/0x11a0 proc_reg_read+0xbc/0x180 do_loop_readv_writev+0x134/0x210 do_readv_writev+0x565/0x660 vfs_readv+0x67/0xa0 do_preadv+0x126/0x170 SyS_preadv+0xc/0x10 do_syscall_64+0x1a1/0x460 return_from_SYSCALL_64+0x0/0x6a CPU: 1 PID: 315 Comm: trinity-c1 Tainted: G B 4.7.0+ #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 ffffea0002d96000 ffff880119b9f918 ffffffff81d6ce81 ffff88011a804480 ffff8800b6581500 ffff880119b9f948 ffffffff8146c7bd ffff88011a804480 ffffea0002d96000 ffff8800b6581500 fffffffffffffff4 ffff880119b9f970 Call Trace: [<ffffffff81d6ce81>] dump_stack+0x65/0x84 [<ffffffff8146c7bd>] print_trailer+0x10d/0x1a0 [<ffffffff814704ff>] object_err+0x2f/0x40 [<ffffffff814754d1>] kasan_report_error+0x221/0x520 [<ffffffff8147590e>] __asan_report_load8_noabort+0x3e/0x40 [<ffffffff83888161>] klist_iter_exit+0x61/0x70 [<ffffffff82404389>] class_dev_iter_exit+0x9/0x10 [<ffffffff81d2e8ea>] disk_seqf_stop+0x3a/0x50 [<ffffffff8151f812>] seq_read+0x4b2/0x11a0 [<ffffffff815f8fdc>] proc_reg_read+0xbc/0x180 [<ffffffff814b24e4>] do_loop_readv_writev+0x134/0x210 [<ffffffff814b4c45>] do_readv_writev+0x565/0x660 [<ffffffff814b8a17>] vfs_readv+0x67/0xa0 [<ffffffff814b8de6>] do_preadv+0x126/0x170 [<ffffffff814b92ec>] SyS_preadv+0xc/0x10 This problem can occur in the following situation: open() - pread() - .seq_start() - iter = kmalloc() // succeeds - seqf->private = iter - .seq_stop() - kfree(seqf->private) - pread() - .seq_start() - iter = kmalloc() // fails - .seq_stop() - class_dev_iter_exit(seqf->private) // boom! old pointer As the comment in disk_seqf_stop() says, stop is called even if start failed, so we need to reinitialise the private pointer to NULL when seq iteration stops. An alternative would be to set the private pointer to NULL when the kmalloc() in disk_seqf_start() fails. Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-10block: fix use-after-free in sys_ioprio_get()Omar Sandoval
commit 8ba8682107ee2ca3347354e018865d8e1967c5f4 upstream. get_task_ioprio() accesses the task->io_context without holding the task lock and thus can race with exit_io_context(), leading to a use-after-free. The reproducer below hits this within a few seconds on my 4-core QEMU VM: #define _GNU_SOURCE #include <assert.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/wait.h> int main(int argc, char **argv) { pid_t pid, child; long nproc, i; /* ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); */ syscall(SYS_ioprio_set, 1, 0, 0x6000); nproc = sysconf(_SC_NPROCESSORS_ONLN); for (i = 0; i < nproc; i++) { pid = fork(); assert(pid != -1); if (pid == 0) { for (;;) { pid = fork(); assert(pid != -1); if (pid == 0) { _exit(0); } else { child = wait(NULL); assert(child == pid); } } } pid = fork(); assert(pid != -1); if (pid == 0) { for (;;) { /* ioprio_get(IOPRIO_WHO_PGRP, 0); */ syscall(SYS_ioprio_get, 2, 0); } } } for (;;) { /* ioprio_get(IOPRIO_WHO_PGRP, 0); */ syscall(SYS_ioprio_get, 2, 0); } return 0; } This gets us KASAN dumps like this: [ 35.526914] ================================================================== [ 35.530009] BUG: KASAN: out-of-bounds in get_task_ioprio+0x7b/0x90 at addr ffff880066f34e6c [ 35.530009] Read of size 2 by task ioprio-gpf/363 [ 35.530009] ============================================================================= [ 35.530009] BUG blkdev_ioc (Not tainted): kasan: bad access detected [ 35.530009] ----------------------------------------------------------------------------- [ 35.530009] Disabling lock debugging due to kernel taint [ 35.530009] INFO: Allocated in create_task_io_context+0x2b/0x370 age=0 cpu=0 pid=360 [ 35.530009] ___slab_alloc+0x55d/0x5a0 [ 35.530009] __slab_alloc.isra.20+0x2b/0x40 [ 35.530009] kmem_cache_alloc_node+0x84/0x200 [ 35.530009] create_task_io_context+0x2b/0x370 [ 35.530009] get_task_io_context+0x92/0xb0 [ 35.530009] copy_process.part.8+0x5029/0x5660 [ 35.530009] _do_fork+0x155/0x7e0 [ 35.530009] SyS_clone+0x19/0x20 [ 35.530009] do_syscall_64+0x195/0x3a0 [ 35.530009] return_from_SYSCALL_64+0x0/0x6a [ 35.530009] INFO: Freed in put_io_context+0xe7/0x120 age=0 cpu=0 pid=1060 [ 35.530009] __slab_free+0x27b/0x3d0 [ 35.530009] kmem_cache_free+0x1fb/0x220 [ 35.530009] put_io_context+0xe7/0x120 [ 35.530009] put_io_context_active+0x238/0x380 [ 35.530009] exit_io_context+0x66/0x80 [ 35.530009] do_exit+0x158e/0x2b90 [ 35.530009] do_group_exit+0xe5/0x2b0 [ 35.530009] SyS_exit_group+0x1d/0x20 [ 35.530009] entry_SYSCALL_64_fastpath+0x1a/0xa4 [ 35.530009] INFO: Slab 0xffffea00019bcd00 objects=20 used=4 fp=0xffff880066f34ff0 flags=0x1fffe0000004080 [ 35.530009] INFO: Object 0xffff880066f34e58 @offset=3672 fp=0x0000000000000001 [ 35.530009] ================================================================== Fix it by grabbing the task lock while we poke at the io_context. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-04block: partition: initialize percpuref before sending out KOBJ_ADDMing Lei
commit b30a337ca27c4f40439e4bfb290cba5f88d73bb7 upstream. The initialization of partition's percpu_ref should have been done before sending out KOBJ_ADD uevent, which may cause userspace to read partition table. So the uninitialized percpu_ref may be accessed in data path. This patch fixes this issue reported by Naveen. Reported-by: Naveen Kaje <nkaje@codeaurora.org> Tested-by: Naveen Kaje <nkaje@codeaurora.org> Fixes: 6c71013ecb7e2(block: partition: convert percpu ref) Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-04-12dm: fix excessive dm-mq context switchingMike Snitzer
commit 6acfe68bac7e6f16dc312157b1fa6e2368985013 upstream. Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower than if an underlying null_blk device were used directly. One of the reasons for this drop in performance is that blk_insert_clone_request() was calling blk_mq_insert_request() with @async=true. This forced the use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues which ushered in ping-ponging between process context (fio in this case) and kblockd's kworker to submit the cloned request. The ftrace function_graph tracer showed: kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to _not_ use kblockd to submit the cloned requests isn't enough to eliminate the observed context switches. In addition to this dm-mq specific blk-core fix, there are 2 DM core fixes to dm-mq that (when paired with the blk-core fix) completely eliminate the observed context switching: 1) don't blk_mq_run_hw_queues in blk-mq request completion Motivated by desire to reduce overhead of dm-mq, punting to kblockd just increases context switches. In my testing against a really fast null_blk device there was no benefit to running blk_mq_run_hw_queues() on completion (and no other blk-mq driver does this). So hopefully this change doesn't induce the need for yet another revert like commit 621739b00e16ca2d ! 2) use blk_mq_complete_request() in dm_complete_request() blk_complete_request() doesn't offer the traditional q->mq_ops vs .request_fn branching pattern that other historic block interfaces do (e.g. blk_get_request). Using blk_mq_complete_request() for blk-mq requests is important for performance. It should be noted that, like blk_complete_request(), blk_mq_complete_request() doesn't natively handle partial completions -- but the request-based DM-multipath target does provide the required partial completion support by dm.c:end_clone_bio() triggering requeueing of the request via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE. dm-mq fix #2 is _much_ more important than #1 for eliminating the context switches. Before: cpu : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475 After: cpu : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472 With these changes multithreaded async read IOPs improved from ~950K to ~1350K for this dm-mq stacked on null_blk test-case. The raw read IOPs of the underlying null_blk device for the same workload is ~1950K. Fixes: 7fb4898e0 ("block: add blk-mq support to blk_insert_cloned_request()") Fixes: bfebd1cdb ("dm: add full blk-mq support to request-based DM") Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-09block: Initialize max_dev_sectors to 0Keith Busch
commit 5f009d3f8e6685fe8c6215082c1696a08b411220 upstream. The new queue limit is not used by the majority of block drivers, and should be initialized to 0 for the driver's requested settings to be used. Signed-off-by: Keith Busch <keith.busch@intel.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-03bio: return EINTR if copying to user space got interruptedHannes Reinecke
commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 upstream. Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for current->mm to see if we have a user space context and only copies data if we do. Now if an IO gets interrupted by a signal data isn't copied into user space any more (as we don't have a user space context) but user space isn't notified about it. This patch modifies the behaviour to return -EINTR from bio_uncopy_user() to notify userland that a signal has interrupted the syscall, otherwise it could lead to a situation where the caller may get a buffer with no data returned. This can be reproduced by issuing SG_IO ioctl()s in one thread while constantly sending signals to it. Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-17block: fix bio splitting on max sectorsMing Lei
commit d0e5fbb01a67e400e82fefe4896ea40c6447ab98 upstream. After commit e36f62042880(block: split bios to maxpossible length), bio can be splitted in the middle of a vector entry, then it is easy to split out one bio which size isn't aligned with block size, especially when the block size is bigger than 512. This patch fixes the issue by making the max io size aligned to logical block size. Fixes: e36f62042880(block: split bios to maxpossible length) Reported-by: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Keith Busch <keith.busch@intel.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-17block: split bios to max possible lengthKeith Busch
commit e36f6204288088fda50d1c84830340ccb70f85ff upstream. This splits bio in the middle of a vector to form the largest possible bio at the h/w's desired alignment, and guarantees the bio being split will have some data. The criteria for splitting is changed from the max sectors to the h/w's optimal sector alignment if it is provided. For h/w that advertise their block storage's underlying chunk size, it's a big performance win to not submit commands that cross them. If sector alignment is not provided, this patch uses the max sectors as before. This addresses the performance issue commit d380561113 attempted to fix, but was reverted due to splitting logic error. Signed-off-by: Keith Busch <keith.busch@intel.com> Cc: Jens Axboe <axboe@fb.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-08Revert "block: Split bios on chunk boundaries"Jens Axboe
This reverts commit d3805611130af9b911e908af9f67a3f64f4f0914. If we end up splitting on the first segment, we don't adjust the sector count. That results in hitting a BUG() with attempting to split 0 sectors. As this is just a performance issue and not a regression since 4.3 release, let's just rever this change. That gives us more time to test a real fix for 4.5, which would be marked for stable anyway.
2015-12-28block: add blk_start_queue_async()Jens Axboe
We currently only have an inline/sync helper to restart a stopped queue. If drivers need an async version, they have to roll their own. Add a generic helper instead. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-22block: Split bios on chunk boundariesKeith Busch
For h/w that advertise their block storage's underlying chunk size, it's a big performance win to not submit commands that cross them. This patch uses that criteria if it is provided. If it is not provided, this patch uses the max sectors as before. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-22Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "Three small fixes for 4.4 final. Specifically: - The segment issue fix from Junichi, where the old IO path does a bio limit split before potentially bouncing the pages. We need to do that in the right order, to ensure that limitations are met. - A NVMe surprise removal IO hang fix from Keith. - A use-after-free in null_blk, introduced by a previous patch in this series. From Mike Krinkin" * 'for-linus' of git://git.kernel.dk/linux-block: null_blk: fix use-after-free error block: ensure to split after potentially bouncing a bio NVMe: IO ending fixes on surprise removal
2015-12-22block: ensure to split after potentially bouncing a bioJunichi Nomura
blk_queue_bio() does split then bounce, which makes the segment counting based on pages before bouncing and could go wrong. Move the split to after bouncing, like we do for blk-mq, and the we fix the issue of having the bio count for segments be wrong. Fixes: 54efd50bfd87 ("block: make generic_make_request handle arbitrarily sized bios") Cc: stable@vger.kernel.org Tested-by: Artem S. Tashkinov <t.artem@lycos.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-12Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "A set of fixes for the current series. This contains: - A bunch of fixes for lightnvm, should be the last round for this series. From Matias and Wenwei. - A writeback detach inode fix from Ilya, also marked for stable. - A block (though it says SCSI) fix for an OOPS in SCSI runtime power management. - Module init error path fixes for null_blk from Minfei" * 'for-linus' of git://git.kernel.dk/linux-block: null_blk: Fix error path in module initialization lightnvm: do not compile in debugging by default lightnvm: prevent gennvm module unload on use lightnvm: fix media mgr registration lightnvm: replace req queue with nvmdev for lld lightnvm: comments on constants lightnvm: check mm before use lightnvm: refactor spin_unlock in gennvm_get_blk lightnvm: put blks when luns configure failed lightnvm: use flags in rrpc_get_blk block: detach bdev inode from its wb in __blkdev_put() SCSI: Fix NULL pointer dereference in runtime PM
2015-12-07Merge branch 'master' into for-4.4-fixesTejun Heo
The following commit which went into mainline through networking tree 3b13758f51de ("cgroups: Allow dynamically changing net_classid") conflicts in net/core/netclassid_cgroup.c with the following pending fix in cgroup/for-4.4-fixes. 1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling") The former separates out update_classid() from cgrp_attach() and updates it to walk all fds of all tasks in the target css so that it can be used from both migration and config change paths. The latter drops @css from cgrp_attach(). Resolve the conflict by making cgrp_attach() call update_classid() with the css from the first task. We can revive @tset walking in cgrp_attach() but given that net_cls is v1 only where there always is only one target css during migration, this is fine. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Nina Schiff <ninasc@fb.com>
2015-12-06Merge tag 'scsi-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi Pull SCSI fixes from James Bottomley: "This is quite a bumper crop of fixes: three from Arnd correcting various build issues in some configurations, a lock recursion in qla2xxx. Two potentially exploitable issues in hpsa and mvsas, a potential null deref in st, a revert of a bdi registration fix that turned out to cause even more problems, a set of fixes to allow people who only defined MPT2SAS to still work after the mpt2/mpt3sas merger and a couple of fixes for issues turned up by the hyper-v storvsc driver" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: mpt3sas: fix Kconfig dependency problem for mpt2sas back compatibility Revert "scsi: Fix a bdi reregistration race" mpt3sas: Add dummy Kconfig option for backwards compatibility Fix a memory leak in scsi_host_dev_release() block/sd: Fix device-imposed transfer length limits scsi_debug: fix prevent_allow+verify regressions MAINTAINERS: Add myself as co-maintainer of the SCSI subsystem. sd: Make discard granularity match logical block size when LBPRZ=1 scsi: hpsa: select CONFIG_SCSI_SAS_ATTR scsi: advansys needs ISA dma api for ISA support scsi_sysfs: protect against double execution of __scsi_remove_device() st: fix potential null pointer dereference. scsi: report 'INQUIRY result too short' once per host advansys: fix big-endian builds qla2xxx: Fix rwlock recursion hpsa: logical vs bitwise AND typo mvsas: don't allow negative timeouts mpt3sas: Fix use sas_is_tlr_enabled API before enabling MPI2_SCSIIO_CONTROL_TLR_ON flag
2015-12-03SCSI: Fix NULL pointer dereference in runtime PMKen Xue
The routines in scsi_pm.c assume that if a runtime-PM callback is invoked for a SCSI device, it can only mean that the device's driver has asked the block layer to handle the runtime power management (by calling blk_pm_runtime_init(), which among other things sets q->dev). However, this assumption turns out to be wrong for things like the ses driver. Normally ses devices are not allowed to do runtime PM, but userspace can override this setting. If this happens, the kernel gets a NULL pointer dereference when blk_post_runtime_resume() tries to use the uninitialized q->dev pointer. This patch fixes the problem by checking q->dev in block layer before handle runtime PM. Since ses doesn't define any PM callbacks and call blk_pm_runtime_init(), the crash won't occur. This fixes Bugzilla #101371. https://bugzilla.kernel.org/show_bug.cgi?id=101371 More discussion can be found from below link. http://marc.info/?l=linux-scsi&m=144163730531875&w=2 Signed-off-by: Ken Xue <Ken.Xue@amd.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: Xiangliang Yu <Xiangliang.Yu@amd.com> Cc: James E.J. Bottomley <JBottomley@odin.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michael Terry <Michael.terry@canonical.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-03Merge branch 'mkp-fixes' into fixesJames Bottomley
2015-12-03cgroup: fix handling of multi-destination migration from subtree_control ↵Tejun Heo
enabling Consider the following v2 hierarchy. P0 (+memory) --- P1 (-memory) --- A \- B P0 has memory enabled in its subtree_control while P1 doesn't. If both A and B contain processes, they would belong to the memory css of P1. Now if memory is enabled on P1's subtree_control, memory csses should be created on both A and B and A's processes should be moved to the former and B's processes the latter. IOW, enabling controllers can cause atomic migrations into different csses. The core cgroup migration logic has been updated accordingly but the controller migration methods haven't and still assume that all tasks migrate to a single target css; furthermore, the methods were fed the css in which subtree_control was updated which is the parent of the target csses. pids controller depends on the migration methods to move charges and this made the controller attribute charges to the wrong csses often triggering the following warning by driving a counter negative. WARNING: CPU: 1 PID: 1 at kernel/cgroup_pids.c:97 pids_cancel.constprop.6+0x31/0x40() Modules linked in: CPU: 1 PID: 1 Comm: systemd Not tainted 4.4.0-rc1+ #29 ... ffffffff81f65382 ffff88007c043b90 ffffffff81551ffc 0000000000000000 ffff88007c043bc8 ffffffff810de202 ffff88007a752000 ffff88007a29ab00 ffff88007c043c80 ffff88007a1d8400 0000000000000001 ffff88007c043bd8 Call Trace: [<ffffffff81551ffc>] dump_stack+0x4e/0x82 [<ffffffff810de202>] warn_slowpath_common+0x82/0xc0 [<ffffffff810de2fa>] warn_slowpath_null+0x1a/0x20 [<ffffffff8118e031>] pids_cancel.constprop.6+0x31/0x40 [<ffffffff8118e0fd>] pids_can_attach+0x6d/0xf0 [<ffffffff81188a4c>] cgroup_taskset_migrate+0x6c/0x330 [<ffffffff81188e05>] cgroup_migrate+0xf5/0x190 [<ffffffff81189016>] cgroup_attach_task+0x176/0x200 [<ffffffff8118949d>] __cgroup_procs_write+0x2ad/0x460 [<ffffffff81189684>] cgroup_procs_write+0x14/0x20 [<ffffffff811854e5>] cgroup_file_write+0x35/0x1c0 [<ffffffff812e26f1>] kernfs_fop_write+0x141/0x190 [<ffffffff81265f88>] __vfs_write+0x28/0xe0 [<ffffffff812666fc>] vfs_write+0xac/0x1a0 [<ffffffff81267019>] SyS_write+0x49/0xb0 [<ffffffff81bcef32>] entry_SYSCALL_64_fastpath+0x12/0x76 This patch fixes the bug by removing @css parameter from the three migration methods, ->can_attach, ->cancel_attach() and ->attach() and updating cgroup_taskset iteration helpers also return the destination css in addition to the task being migrated. All controllers are updated accordingly. * Controllers which don't care whether there are one or multiple target csses can be converted trivially. cpu, io, freezer, perf, netclassid and netprio fall in this category. * cpuset's current implementation assumes that there's single source and destination and thus doesn't support v2 hierarchy already. The only change made by this patchset is how that single destination css is obtained. * memory migration path already doesn't do anything on v2. How the single destination css is obtained is updated and the prep stage of mem_cgroup_can_attach() is reordered to accomodate the change. * pids is the only controller which was affected by this bug. It now correctly handles multi-destination migrations and no longer causes counter underflow from incorrect accounting. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Aleksa Sarai <cyphar@cyphar.com>
2015-11-30blk-merge: fix computing bio->bi_seg_front_size in case of single segmentMing Lei
When bio has only one physical segment, we should set bio's bi_seg_front_size as the real(final) size of the single segment. Fixes: 02e707424c2ea(blk-merge: fix blk_bio_segment_split) Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-29block: Always check queue limits for cloned requestsHannes Reinecke
When a cloned request is retried on other queues it always needs to be checked against the queue limits of that queue. Otherwise the calculations for nr_phys_segments might be wrong, leading to a crash in scsi_init_sgtable(). To clarify this the patch renames blk_rq_check_limits() to blk_cloned_rq_check_limits() and removes the symbol export, as the new function should only be used for cloned requests and never exported. Cc: Mike Snitzer <snitzer@redhat.com> Cc: Ewan Milne <emilne@redhat.com> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Fixes: e2a60da74 ("block: Clean up special command handling logic") Cc: stable@vger.kernel.org # 3.7+ Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25Return EBUSY from BLKRRPART for mounted whole-dev fsEric Sandeen
Today, blockdev --rereadpt /dev/sda will fail with EBUSY if any partition of sda is mounted (and will fail with EINVAL if pointed at a partition). But it will pass if the entire block device is formatted with a filesystem and mounted. I don't think this makes sense; partitioning should surely not ever change out from under a mounted device. So check for bdev->bd_super, and fail that with -EBUSY as well. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25block/sd: Fix device-imposed transfer length limitsMartin K. Petersen
Commit 4f258a46346c ("sd: Fix maximum I/O size for BLOCK_PC requests") had the unfortunate side-effect of removing an implicit clamp to BLK_DEF_MAX_SECTORS for REQ_TYPE_FS requests in the block layer code. This caused problems for some SMR drives. Debugging this issue revealed a few problems with the existing infrastructure since the block layer didn't know how to deal with device-imposed limits, only limits set by the I/O controller. - Introduce a new queue limit, max_dev_sectors, which is used by the ULD to signal the maximum sectors for a REQ_TYPE_FS request. - Ensure that max_dev_sectors is correctly stacked and taken into account when overriding max_sectors through sysfs. - Rework sd_read_block_limits() so it saves the max_xfer and opt_xfer values for later processing. - In sd_revalidate() set the queue's max_dev_sectors based on the MAXIMUM TRANSFER LENGTH value in the Block Limits VPD. If this value is not reported, fall back to a cap based on the CDB TRANSFER LENGTH field size. - In sd_revalidate(), use OPTIMAL TRANSFER LENGTH from the Block Limits VPD--if reported and sane--to signal the preferred device transfer size for FS requests. Otherwise use BLK_DEF_MAX_SECTORS. - blk_limits_max_hw_sectors() is no longer used and can be removed. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581 Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: sweeneygj@gmx.com Tested-by: Arzeets <anatol.pomozov@gmail.com> Tested-by: David Eisner <david.eisner@oriel.oxon.org> Tested-by: Mario Kicherer <dev@kicherer.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2015-11-25Revert "blk-flush: Queue through IO scheduler when flush not required"Jens Axboe
This reverts commit 1b2ff19e6a957b1ef0f365ad331b608af80e932e. Jan writes: -- Thanks for report! After some investigation I found out we allocate elevator specific data in __get_request() only for non-flush requests. And this is actually required since the flush machinery uses the space in struct request for something else. Doh. So my patch is just wrong and not easy to fix since at the time __get_request() is called we are not sure whether the flush machinery will be used in the end. Jens, please revert 1b2ff19e6a957b1ef0f365ad331b608af80e932e. Thanks! I'm somewhat surprised that you can reliably hit the race where flushing gets disabled for the device just while the request is in flight. But I guess during boot it makes some sense. -- So let's just revert it, we can fix the queue run manually after the fact. This race is rare enough that it didn't trigger in testing, it requires the specific disable-while-in-flight scenario to trigger.
2015-11-24block: fix blk_abort_request for blk-mq driversChristoph Hellwig
We only added the request to the request list for the !blk-mq case, so we should only delete it in that case as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "A round of fixes/updates for the current series. This looks a little bigger than it is, but that's mainly because we pushed the lightnvm enabled null_blk change out of the merge window so it could be updated a bit. The rest of the volume is also mostly lightnvm. In particular: - Lightnvm. Various fixes, additions, updates from Matias and Javier, as well as from Wenwei Tao. - NVMe: - Fix for potential arithmetic overflow from Keith. - Also from Keith, ensure that we reap pending completions from a completion queue before deleting it. Fixes kernel crashes when resetting a device with IO pending. - Various little lightnvm related tweaks from Matias. - Fixup flushes to go through the IO scheduler, for the cases where a flush is not required. Fixes a case in CFQ where we would be idling and not see this request, hence not break the idling. From Jan Kara. - Use list_{first,prev,next} in elevator.c for cleaner code. From Gelian Tang. - Fix for a warning trigger on btrfs and raid on single queue blk-mq devices, where we would flush plug callbacks with preemption disabled. From me. - A mac partition validation fix from Kees Cook. - Two merge fixes from Ming, marked stable. A third part is adding a new warning so we'll notice this quicker in the future, if we screw up the accounting. - Cleanup of thread name/creation in mtip32xx from Rasmus Villemoes" * 'for-linus' of git://git.kernel.dk/linux-block: (32 commits) blk-merge: warn if figured out segment number is bigger than nr_phys_segments blk-merge: fix blk_bio_segment_split block: fix segment split blk-mq: fix calling unplug callbacks with preempt disabled mac: validate mac_partition is within sector mtip32xx: use formatting capability of kthread_create_on_node NVMe: reap completion entries when deleting queue lightnvm: add free and bad lun info to show luns lightnvm: keep track of block counts nvme: lightnvm: use admin queues for admin cmds lightnvm: missing free on init error lightnvm: wrong return value and redundant free null_blk: do not del gendisk with lightnvm null_blk: use device addressing mode null_blk: use ppa_cache pool NVMe: Fix possible arithmetic overflow for max segments blk-flush: Queue through IO scheduler when flush not required null_blk: register as a LightNVM device elevator: use list_{first,prev,next}_entry lightnvm: cleanup queue before target removal ...
2015-11-23blk-merge: warn if figured out segment number is bigger than nr_phys_segmentsMing Lei
We had seen lots of reports of this kind issue, so add one warnning in blk-merge, then it can be triggered easily and avoid to depend on warning/bug from drivers. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-23blk-merge: fix blk_bio_segment_splitMing Lei
Commit bdced438acd83a(block: setup bi_phys_segments after splitting) introduces function of computing bio->bi_phys_segments during bio splitting. Unfortunately both bio->bi_seg_front_size and bio->bi_seg_back_size arn't computed, so too many physical segments may be obtained for one request since both the two are used to check if one segment across two bios can be possible. This patch fixes the issue by computing the two variables in blk_bio_segment_split(). Fixes: bdced438acd83a(block: setup bi_phys_segments after splitting) Reported-by: Michael Ellerman <mpe@ellerman.id.au> Reported-by: Mark Salter <msalter@redhat.com> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Tested-by: Mark Salter <msalter@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-23block: fix segment splitMing Lei
Inside blk_bio_segment_split(), previous bvec pointer(bvprvp) always points to the iterator local variable, which is obviously wrong, so fix it by pointing to the local variable of 'bvprv'. Fixes: 5014c311baa2b(block: fix bogus compiler warnings in blk-merge.c) Cc: stable@kernel.org #4.3 Reported-by: Michael Ellerman <mpe@ellerman.id.au> Reported-by: Mark Salter <msalter@redhat.com> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Tested-by: Mark Salter <msalter@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-20blk-mq: fix calling unplug callbacks with preempt disabledJens Axboe
Liu reported that running certain parts of xfstests threw the following error: BUG: sleeping function called from invalid context at mm/page_alloc.c:3190 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0 3 locks held by kworker/u16:0/6: #0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 #2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60 CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3 Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 Workqueue: writeback wb_workfn (flush-btrfs-108) ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8 ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76 Call Trace: [<ffffffff8130191b>] dump_stack+0x4f/0x74 [<ffffffff8108ed95>] ___might_sleep+0x185/0x240 [<ffffffff8108eea2>] __might_sleep+0x52/0x90 [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410 [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90 [<ffffffff8109a6d1>] ? local_clock+0x21/0x40 [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510 [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0 [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210 [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs] [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60 [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs] [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs] [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs] [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs] [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0 [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740 [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0 [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310 [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310 [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0 [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0 [<ffffffff812d0ca0>] submit_bio+0x70/0x140 [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs] [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs] [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs] [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs] [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs] [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs] [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs] [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs] [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs] [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs] [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs] [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs] [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs] [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs] [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs] [<ffffffff81184df3>] do_writepages+0x23/0x40 [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480 [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480 [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60 [<ffffffff811e6805>] ? trylock_super+0x25/0x60 [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90 [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0 [<ffffffff812130b5>] wb_writeback+0x2b5/0x500 [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0 [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310 [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310 [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90 [<ffffffff81213842>] wb_workfn+0x92/0x330 [<ffffffff8107f133>] process_one_work+0x223/0x730 [<ffffffff8107f083>] ? process_one_work+0x173/0x730 [<ffffffff8108035f>] ? worker_thread+0x18f/0x430 [<ffffffff810802ed>] worker_thread+0x11d/0x430 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 [<ffffffff810858df>] kthread+0xef/0x110 [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 [<ffffffff816673bf>] ret_from_fork+0x3f/0x70 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 The issue is that we've got the software context pinned while calling blk_flush_plug_list(), which flushes callbacks that are allowed to sleep. btrfs and raid has such callbacks. Flip the checks around a bit, so we can enable preempt a bit earlier and flush plugs without having preempt disabled. This only affects blk-mq driven devices, and only those that register a single queue. Reported-by: Liu Bo <bo.li.liu@oracle.com> Tested-by: Liu Bo <bo.li.liu@oracle.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-20mac: validate mac_partition is within sectorKees Cook
If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single 512 byte sector would be read (secsize / 512). However the partition structure would be located past the end of the buffer (secsize % 512). Signed-off-by: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-19block: protect rw_page against device teardownDan Williams
Fix use after free crashes like the following: general protection fault: 0000 [#1] SMP Call Trace: [<ffffffffa0050216>] ? pmem_do_bvec.isra.12+0xa6/0xf0 [nd_pmem] [<ffffffffa0050ba2>] pmem_rw_page+0x42/0x80 [nd_pmem] [<ffffffff8128fd90>] bdev_read_page+0x50/0x60 [<ffffffff812972f0>] do_mpage_readpage+0x510/0x770 [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20 [<ffffffff811d86dc>] ? lru_cache_add+0x1c/0x50 [<ffffffff81297657>] mpage_readpages+0x107/0x170 [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20 [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20 [<ffffffff8129058d>] blkdev_readpages+0x1d/0x20 [<ffffffff811d615f>] __do_page_cache_readahead+0x28f/0x310 [<ffffffff811d6039>] ? __do_page_cache_readahead+0x169/0x310 [<ffffffff811c5abd>] ? pagecache_get_page+0x2d/0x1d0 [<ffffffff811c76f6>] filemap_fault+0x396/0x530 [<ffffffff811f816e>] __do_fault+0x4e/0xf0 [<ffffffff811fce7d>] handle_mm_fault+0x11bd/0x1b50 Cc: <stable@vger.kernel.org> Cc: Jens Axboe <axboe@fb.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Reported-by: kbuild test robot <lkp@intel.com> Acked-by: Matthew Wilcox <willy@linux.intel.com> [willy: symmetry fixups] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-11-16blk-flush: Queue through IO scheduler when flush not requiredJan Kara
Currently blk_insert_flush() just adds flush request to q->queue_head when flush is not required. That completely bypasses IO scheduler so e.g. CFQ can be idling waiting for new request to arrive and will idle through the whole window unnecessarily. Luckily this only happens in rare cases as usually checks in generic_make_request_checks() clear FLUSH and FUA flags early if they are not needed. When no flushing is actually required, we can easily fix the problem by properly queueing the request through the IO scheduler. Ideally IO scheduler should be also made aware of requests queued via blk_flush_queue_rq(). However inserting flush request through IO scheduler can have unwanted side-effects since due to flush batching delaying the flush request in IO scheduler will delay all flush requests possibly coming from other processes. So we keep adding the request directly to q->queue_head. Signed-off-by: Jan Kara <jack@suse.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-16elevator: use list_{first,prev,next}_entryGeliang Tang
To make the intention clearer, use list_{first,prev,next}_entry instead of list_entry. Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-11block: fix blk-core.c kernel-doc warningRandy Dunlap
Fix kernel-doc warning in blk-core.c: Warning(..//block/blk-core.c:1549): No description found for parameter 'same_queue_rq' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-11blk-mq: mark __blk_mq_complete_request() staticJens Axboe
It's no longer used outside of blk-mq core. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-10Merge branch 'for-4.4/io-poll' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block IO poll support from Jens Axboe: "Various groups have been doing experimentation around IO polling for (really) fast devices. The code has been reviewed and has been sitting on the side for a few releases, but this is now good enough for coordinated benchmarking and further experimentation. Currently O_DIRECT sync read/write are supported. A framework is in the works that allows scalable stats tracking so we can auto-tune this. And we'll add libaio support as well soon. Fow now, it's an opt-in feature for test purposes" * 'for-4.4/io-poll' of git://git.kernel.dk/linux-block: direct-io: be sure to assign dio->bio_bdev for both paths directio: add block polling support NVMe: add blk polling support block: add block polling support blk-mq: return tag/queue combo in the make_request_fn handlers block: change ->make_request_fn() and users to return a queue cookie
2015-11-07block: add block polling supportJens Axboe
Add basic support for polling for specific IO to complete. This uses the cookie that blk-mq passes back, which enables the block layer to pass this cookie to the driver to spin for a specific request. This will be combined with request latency tracking, so we can make qualified decisions about when to poll and when not to. For now, for benchmark purposes, we add a sysfs file that controls whether polling is enabled or not. Signed-off-by: Jens Axboe <axboe@fb.com> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Keith Busch <keith.busch@intel.com>
2015-11-07blk-mq: return tag/queue combo in the make_request_fn handlersJens Axboe
Return a cookie, blk_qc_t, from the blk-mq make request functions, that allows a later caller to uniquely identify a specific IO. The cookie doesn't mean anything to the caller, but the caller can use it to later pass back to the block layer. The block layer can then identify the hardware queue and request from that cookie. Signed-off-by: Jens Axboe <axboe@fb.com> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Keith Busch <keith.busch@intel.com>
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