Re: WARNING in __vm_enough_memory

[Dmitry Vyukov]

On Tue, Jan 16, 2018 at 12:58 AM, syzbot
<syzbot+cc298e15b6a571ba0c55@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
>
> syzkaller hit the following crash on
> 8418f88764046d0e8ca6a3c04a69a0e57189aa1e
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers


Most likely it is drivers/staging/android/ashmem.c which is guilty. So
+ashmem maintainers.


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> Reported-by: syzbot+cc298e15b6a571ba0c55@xxxxxxxxxxxxxxxxxxxxxxxxx
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>
> audit: type=1400 audit(1515720420.441:8): avc:  denied  { sys_admin } for
> pid=3511 comm="syzkaller485245" capability=21
> scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
> tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns
> permissive=1
> audit: type=1400 audit(1515720420.495:9): avc:  denied  { sys_chroot } for
> pid=3512 comm="syzkaller485245" capability=18
> scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
> tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns
> permissive=1
> ------------[ cut here ]------------
> memory commitment underflow
> WARNING: CPU: 0 PID: 3512 at mm/util.c:606 __vm_enough_memory+0x5a6/0x810
> mm/util.c:604
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 0 PID: 3512 Comm: syzkaller485245 Not tainted 4.15.0-rc7-next-20180111+
> #94
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:53
>  panic+0x1e4/0x41c kernel/panic.c:183
>  __warn+0x1dc/0x200 kernel/panic.c:547
>  report_bug+0x211/0x2d0 lib/bug.c:184
>  fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
>  fixup_bug arch/x86/kernel/traps.c:247 [inline]
>  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
>  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
>  invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1102
> RIP: 0010:__vm_enough_memory+0x5a6/0x810 mm/util.c:604
> RSP: 0018:ffff8801bfbaf8e0 EFLAGS: 00010282
> RAX: dffffc0000000008 RBX: 1ffff10037f75f21 RCX: ffffffff815a613e
> RDX: 0000000000000000 RSI: 1ffff10037e84d3b RDI: 0000000000000293
> RBP: ffff8801bfbafa90 R08: 1ffff10037f75eaf R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801bfbafa68
> R13: ffffffff869b8c80 R14: 0000000000000fff R15: dffffc0000000000
>  security_vm_enough_memory_mm+0x90/0xb0 security/security.c:327
>  mmap_region+0x321/0x15a0 mm/mmap.c:1666
>  do_mmap+0x73c/0xf70 mm/mmap.c:1494
>  do_mmap_pgoff include/linux/mm.h:2224 [inline]
>  vm_mmap_pgoff+0x1de/0x280 mm/util.c:333
>  SYSC_mmap_pgoff mm/mmap.c:1544 [inline]
>  SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1502
>  SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
>  SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91
>  entry_SYSCALL_64_fastpath+0x29/0xa0
> RIP: 0033:0x440ac9
> RSP: 002b:00000000007dff58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009
> RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440ac9
> RDX: 0000000000000003 RSI: 0000000000fff000 RDI: 0000000020000000
> RBP: 7fffffffffffffff R08: 00000000ffffffff R09: 0000000000000000
> R10: 0000000000000032 R11: 0000000000000212 R12: 6873612f7665642f
> R13: 6c616b7a79732f2e R14: 0000000000000000 R15: 0000000000000000
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
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