This prevents bad inode numbers from triggering errors in ext2_get_inode. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Mirror the bug fix from fill_packet_ipv4() Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Chen-Li Tien <cltien@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Jack Steiner identified a problem where XPC can cause a silent data corruption. On module load, the placement may cause the xpc_remote_copy_buffer to span two physical pages. DMA transfers are done to the start virtual address translated to physical. This patch changes the buffer from a statically allocated buffer to a kmalloc'd buffer. Dean Nelson reviewed this before posting. I have tested it in the configuration that was showing the memory corruption and verified it works. I also added a BUG_ON statement to help catch this if a similar situation is encountered. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Dean Nelson <dcn@sgi.com> Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Bug noticed by Remi Denis-Courmont <rdenis@simphalempin.com>. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
I ran into a bug where the kernel died in the idr code:
cpu 0x1d: Vector: 300 (Data Access) at [c000000b7096f710]
pc: c0000000001f8984: .idr_get_new_above_int+0x140/0x330
lr: c0000000001f89b4: .idr_get_new_above_int+0x170/0x330
sp: c000000b7096f990
msr: 800000000000b032
dar: 0
dsisr: 40010000
current = 0xc000000b70d43830
paca = 0xc000000000556900
pid = 2022, comm = hwup
1d:mon> t
[c000000b7096f990] c0000000000d2ad8 .expand_files+0x2e8/0x364 (unreliable)
[c000000b7096faa0] c0000000001f8bf8 .idr_get_new_above+0x18/0x68
[c000000b7096fb20] c00000000002a054 .init_new_context+0x5c/0xf0
[c000000b7096fbc0] c000000000049dc8 .copy_process+0x91c/0x1404
[c000000b7096fcd0] c00000000004a988 .do_fork+0xd8/0x224
[c000000b7096fdc0] c00000000000ebdc .sys_clone+0x5c/0x74
[c000000b7096fe30] c000000000008950 .ppc_clone+0x8/0xc
-- Exception: c00 (System Call) at 000000000fde887c
SP (f8b4e7a0) is in userspace
Turned out to be a race-condition and NULL ptr deref, here's my fix:
Users of the idr code are supposed to call idr_pre_get without locking, so the
idr code must serialize itself with respect to layer allocations. However, it
fails to do so in an error path in idr_get_new_above_int(). I added the
missing locking to fix this.
Signed-off-by: Sonny Rao <sonny@burdell.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch adds a barrier() in futex unqueue_me to avoid aliasing of two
pointers.
On my s390x system I saw the following oops:
Unable to handle kernel pointer dereference at virtual kernel address
0000000000000000
Oops: 0004 [#1]
CPU: 0 Not tainted
Process mytool (pid: 13613, task: 000000003ecb6ac0, ksp: 00000000366bdbd8)
Krnl PSW : 0704d00180000000 00000000003c9ac2 (_spin_lock+0xe/0x30)
Krnl GPRS: 00000000ffffffff 000000003ecb6ac0 0000000000000000 0700000000000000
0000000000000000 0000000000000000 000001fe00002028 00000000000c091f
000001fe00002054 000001fe00002054 0000000000000000 00000000366bddc0
00000000005ef8c0 00000000003d00e8 0000000000144f91 00000000366bdcb8
Krnl Code: ba 4e 20 00 12 44 b9 16 00 3e a7 84 00 08 e3 e0 f0 88 00 04
Call Trace:
([<0000000000144f90>] unqueue_me+0x40/0xe4)
[<0000000000145a0c>] do_futex+0x33c/0xc40
[<000000000014643e>] sys_futex+0x12e/0x144
[<000000000010bb00>] sysc_noemu+0x10/0x16
[<000002000003741c>] 0x2000003741c
The code in question is:
static int unqueue_me(struct futex_q *q)
{
int ret = 0;
spinlock_t *lock_ptr;
/* In the common case we don't take the spinlock, which is nice. */
retry:
lock_ptr = q->lock_ptr;
if (lock_ptr != 0) {
spin_lock(lock_ptr);
/*
* q->lock_ptr can change between reading it and
* spin_lock(), causing us to take the wrong lock. This
* corrects the race condition.
[...]
and my compiler (gcc 4.1.0) makes the following out of it:
00000000000003c8 <unqueue_me>:
3c8: eb bf f0 70 00 24 stmg %r11,%r15,112(%r15)
3ce: c0 d0 00 00 00 00 larl %r13,3ce <unqueue_me+0x6>
3d0: R_390_PC32DBL .rodata+0x2a
3d4: a7 f1 1e 00 tml %r15,7680
3d8: a7 84 00 01 je 3da <unqueue_me+0x12>
3dc: b9 04 00 ef lgr %r14,%r15
3e0: a7 fb ff d0 aghi %r15,-48
3e4: b9 04 00 b2 lgr %r11,%r2
3e8: e3 e0 f0 98 00 24 stg %r14,152(%r15)
3ee: e3 c0 b0 28 00 04 lg %r12,40(%r11)
/* write q->lock_ptr in r12 */
3f4: b9 02 00 cc ltgr %r12,%r12
3f8: a7 84 00 4b je 48e <unqueue_me+0xc6>
/* if r12 is zero then jump over the code.... */
3fc: e3 20 b0 28 00 04 lg %r2,40(%r11)
/* write q->lock_ptr in r2 */
402: c0 e5 00 00 00 00 brasl %r14,402 <unqueue_me+0x3a>
404: R_390_PC32DBL _spin_lock+0x2
/* use r2 as parameter for spin_lock */
So the code becomes more or less:
if (q->lock_ptr != 0) spin_lock(q->lock_ptr)
instead of
if (lock_ptr != 0) spin_lock(lock_ptr)
Which caused the oops from above.
After adding a barrier gcc creates code without this problem:
[...] (the same)
3ee: e3 c0 b0 28 00 04 lg %r12,40(%r11)
3f4: b9 02 00 cc ltgr %r12,%r12
3f8: b9 04 00 2c lgr %r2,%r12
3fc: a7 84 00 48 je 48c <unqueue_me+0xc4>
400: c0 e5 00 00 00 00 brasl %r14,400 <unqueue_me+0x38>
402: R_390_PC32DBL _spin_lock+0x2
As a general note, this code of unqueue_me seems a bit fishy. The retry logic
of unqueue_me only works if we can guarantee, that the original value of
q->lock_ptr is always a spinlock (Otherwise we overwrite kernel memory). We
know that q->lock_ptr can change. I dont know what happens with the original
spinlock, as I am not an expert with the futex code.
Signed-off-by: Christian Borntraeger <borntrae@de.ibm.com>
Acked-by: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>