* KASAN: alloca-out-of-bounds Read in unwind_next_frame
@ 2018-04-06 0:02 syzbot
2018-04-06 9:09 ` Dmitry Vyukov
2018-04-06 15:36 ` Josh Poimboeuf
0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2018-04-06 0:02 UTC (permalink / raw)
To: hpa, jpoimboe, linux-kernel, mhiramat, mingo, syzkaller-bugs, tglx, x86
Hello,
syzbot hit the following crash on upstream commit
06dd3dfeea60e2a6457a6aedf97afc8e6d2ba497 (Thu Apr 5 03:07:20 2018 +0000)
Merge tag 'char-misc-4.17-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=9d1d9866b0b8ee6e0a8c
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=6478299081474048
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5324218015154176
Kernel config: https://syzkaller.appspot.com/x/.config?id=216543573824217049
compiler: gcc (GCC) 8.0.1 20180301 (experimental)
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9d1d9866b0b8ee6e0a8c@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.
==================================================================
BUG: KASAN: alloca-out-of-bounds in __read_once_size
include/linux/compiler.h:188 [inline]
BUG: KASAN: alloca-out-of-bounds in unwind_next_frame.part.7+0x7ce/0x9c0
arch/x86/kernel/unwind_frame.c:326
Read of size 8 at addr ffff8801b05e67f8 by task syz-executor2/11326
CPU: 0 PID: 11326 Comm: syz-executor2 Not tainted 4.16.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b9/0x29f lib/dump_stack.c:53
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
__read_once_size include/linux/compiler.h:188 [inline]
unwind_next_frame.part.7+0x7ce/0x9c0 arch/x86/kernel/unwind_frame.c:326
unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6e/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
__cache_free mm/slab.c:3486 [inline]
kmem_cache_free+0x86/0x2d0 mm/slab.c:3744
__d_free+0x20/0x30 fs/dcache.c:257
__rcu_reclaim kernel/rcu/rcu.h:178 [inline]
rcu_do_batch kernel/rcu/tree.c:2675 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2930 [inline]
__rcu_process_callbacks kernel/rcu/tree.c:2897 [inline]
rcu_process_callbacks+0x941/0x15f0 kernel/rcu/tree.c:2914
__do_softirq+0x2e0/0xaf5 kernel/softirq.c:285
invoke_softirq kernel/softirq.c:365 [inline]
irq_exit+0x1d1/0x200 kernel/softirq.c:405
exiting_irq arch/x86/include/asm/apic.h:525 [inline]
smp_apic_timer_interrupt+0x17e/0x710 arch/x86/kernel/apic/apic.c:1052
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
</IRQ>
RIP: 0010:kasan_unpoison_shadow+0x1/0x50 mm/kasan/kasan.c:68
RSP: 0018:ffff8801b05e67e8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: ffff8801c1b24100 RBX: 0000000000000000 RCX: ffffffff859d4219
RDX: 0000000000000000 RSI: 00000000000000a8 RDI: ffff8801b05e6760
RBP: ffff8801b05e67f8 R08: ffff8801c1b24100 R09: ffffed003b6046c2
R10: ffffed003b6046c2 R11: ffff8801db023613 R12: 0000000000000015
R13: 0000000000000001 R14: 0000000000000016 R15: dffffc0000000000
constrain_params_by_rules+0xbaa/0x1410 sound/core/pcm_param_trace.h:28
snd_pcm_hw_refine+0x8e9/0x1180 sound/core/pcm_native.c:502
snd_pcm_hw_param_mask sound/core/oss/pcm_oss.c:205 [inline]
snd_pcm_oss_change_params+0x8ce/0x3d10 sound/core/oss/pcm_oss.c:870
snd_pcm_oss_make_ready+0xe3/0x140 sound/core/oss/pcm_oss.c:1127
snd_pcm_oss_sync.isra.27+0x24b/0x850 sound/core/oss/pcm_oss.c:1651
snd_pcm_oss_release+0x214/0x290 sound/core/oss/pcm_oss.c:2446
__fput+0x34d/0x890 fs/file_table.c:209
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x1e4/0x290 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1aee/0x2730 kernel/exit.c:865
do_group_exit+0x16f/0x430 kernel/exit.c:968
get_signal+0x886/0x1960 kernel/signal.c:2469
do_signal+0x90/0x2020 arch/x86/kernel/signal.c:810
exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4552d9
RSP: 002b:00007fd689eb5c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fd689eb66d4 RCX: 00000000004552d9
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 000000000000000f
RBP: 000000000072c010 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000027d R14: 00000000006f6c58 R15: 0000000000000002
The buggy address belongs to the page:
page:ffffea0006c17980 count:0 mapcount:0 mapping:0000000000000000
index:0xffff8801b05e69c0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffff8801b05e69c0 00000000ffffffff
raw: dead000000000100 dead000000000200 ffff8801dad7f600 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801b05e6680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801b05e6700: 00 00 00 00 00 00 00 00 00 00 00 00 ca ca ca ca
> ffff8801b05e6780: 00 00 00 00 00 00 00 00 00 00 04 cb cb cb cb cb
^
ffff8801b05e6800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801b05e6880: 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2
==================================================================
---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@googlegroups.com.
syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is
merged
into any tree, please reply to this email with:
#syz fix: exact-commit-title
If you want to test a patch for this bug, please reply with:
#syz test: git://repo/address.git branch
and provide the patch inline or as an attachment.
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: alloca-out-of-bounds Read in unwind_next_frame
2018-04-06 0:02 KASAN: alloca-out-of-bounds Read in unwind_next_frame syzbot
@ 2018-04-06 9:09 ` Dmitry Vyukov
2018-04-06 15:36 ` Josh Poimboeuf
1 sibling, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2018-04-06 9:09 UTC (permalink / raw)
To: syzbot
Cc: H. Peter Anvin, Josh Poimboeuf, LKML, Masami Hiramatsu,
Ingo Molnar, syzkaller-bugs, Thomas Gleixner,
the arch/x86 maintainers
On Fri, Apr 6, 2018 at 2:02 AM, syzbot
<syzbot+9d1d9866b0b8ee6e0a8c@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 06dd3dfeea60e2a6457a6aedf97afc8e6d2ba497 (Thu Apr 5 03:07:20 2018 +0000)
> Merge tag 'char-misc-4.17-rc1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=9d1d9866b0b8ee6e0a8c
>
> syzkaller reproducer:
> https://syzkaller.appspot.com/x/repro.syz?id=6478299081474048
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=5324218015154176
> Kernel config: https://syzkaller.appspot.com/x/.config?id=216543573824217049
> compiler: gcc (GCC) 8.0.1 20180301 (experimental)
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9d1d9866b0b8ee6e0a8c@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
This looks like a false positives related to interactions between
alloca, interrupts, KASAN and -mno-red-zones. I've filed gcc bug for
this:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85230
> ==================================================================
> BUG: KASAN: alloca-out-of-bounds in __read_once_size
> include/linux/compiler.h:188 [inline]
> BUG: KASAN: alloca-out-of-bounds in unwind_next_frame.part.7+0x7ce/0x9c0
> arch/x86/kernel/unwind_frame.c:326
> Read of size 8 at addr ffff8801b05e67f8 by task syz-executor2/11326
>
> CPU: 0 PID: 11326 Comm: syz-executor2 Not tainted 4.16.0+ #1
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:17 [inline]
> dump_stack+0x1b9/0x29f lib/dump_stack.c:53
> print_address_description+0x6c/0x20b mm/kasan/report.c:256
> kasan_report_error mm/kasan/report.c:354 [inline]
> kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
> __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
> __read_once_size include/linux/compiler.h:188 [inline]
> unwind_next_frame.part.7+0x7ce/0x9c0 arch/x86/kernel/unwind_frame.c:326
> unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
> __save_stack_trace+0x6e/0xd0 arch/x86/kernel/stacktrace.c:44
> save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
> save_stack+0x43/0xd0 mm/kasan/kasan.c:447
> set_track mm/kasan/kasan.c:459 [inline]
> __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
> kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
> __cache_free mm/slab.c:3486 [inline]
> kmem_cache_free+0x86/0x2d0 mm/slab.c:3744
> __d_free+0x20/0x30 fs/dcache.c:257
> __rcu_reclaim kernel/rcu/rcu.h:178 [inline]
> rcu_do_batch kernel/rcu/tree.c:2675 [inline]
> invoke_rcu_callbacks kernel/rcu/tree.c:2930 [inline]
> __rcu_process_callbacks kernel/rcu/tree.c:2897 [inline]
> rcu_process_callbacks+0x941/0x15f0 kernel/rcu/tree.c:2914
> __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285
> invoke_softirq kernel/softirq.c:365 [inline]
> irq_exit+0x1d1/0x200 kernel/softirq.c:405
> exiting_irq arch/x86/include/asm/apic.h:525 [inline]
> smp_apic_timer_interrupt+0x17e/0x710 arch/x86/kernel/apic/apic.c:1052
> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
> </IRQ>
> RIP: 0010:kasan_unpoison_shadow+0x1/0x50 mm/kasan/kasan.c:68
> RSP: 0018:ffff8801b05e67e8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
> RAX: ffff8801c1b24100 RBX: 0000000000000000 RCX: ffffffff859d4219
> RDX: 0000000000000000 RSI: 00000000000000a8 RDI: ffff8801b05e6760
> RBP: ffff8801b05e67f8 R08: ffff8801c1b24100 R09: ffffed003b6046c2
> R10: ffffed003b6046c2 R11: ffff8801db023613 R12: 0000000000000015
> R13: 0000000000000001 R14: 0000000000000016 R15: dffffc0000000000
> constrain_params_by_rules+0xbaa/0x1410 sound/core/pcm_param_trace.h:28
> snd_pcm_hw_refine+0x8e9/0x1180 sound/core/pcm_native.c:502
> snd_pcm_hw_param_mask sound/core/oss/pcm_oss.c:205 [inline]
> snd_pcm_oss_change_params+0x8ce/0x3d10 sound/core/oss/pcm_oss.c:870
> snd_pcm_oss_make_ready+0xe3/0x140 sound/core/oss/pcm_oss.c:1127
> snd_pcm_oss_sync.isra.27+0x24b/0x850 sound/core/oss/pcm_oss.c:1651
> snd_pcm_oss_release+0x214/0x290 sound/core/oss/pcm_oss.c:2446
> __fput+0x34d/0x890 fs/file_table.c:209
> ____fput+0x15/0x20 fs/file_table.c:243
> task_work_run+0x1e4/0x290 kernel/task_work.c:113
> exit_task_work include/linux/task_work.h:22 [inline]
> do_exit+0x1aee/0x2730 kernel/exit.c:865
> do_group_exit+0x16f/0x430 kernel/exit.c:968
> get_signal+0x886/0x1960 kernel/signal.c:2469
> do_signal+0x90/0x2020 arch/x86/kernel/signal.c:810
> exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
> prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
> syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
> do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292
> entry_SYSCALL_64_after_hwframe+0x42/0xb7
> RIP: 0033:0x4552d9
> RSP: 002b:00007fd689eb5c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: 0000000000000000 RBX: 00007fd689eb66d4 RCX: 00000000004552d9
> RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 000000000000000f
> RBP: 000000000072c010 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
> R13: 000000000000027d R14: 00000000006f6c58 R15: 0000000000000002
>
> The buggy address belongs to the page:
> page:ffffea0006c17980 count:0 mapcount:0 mapping:0000000000000000
> index:0xffff8801b05e69c0
> flags: 0x2fffc0000000000()
> raw: 02fffc0000000000 0000000000000000 ffff8801b05e69c0 00000000ffffffff
> raw: dead000000000100 dead000000000200 ffff8801dad7f600 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> ffff8801b05e6680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8801b05e6700: 00 00 00 00 00 00 00 00 00 00 00 00 ca ca ca ca
>>
>> ffff8801b05e6780: 00 00 00 00 00 00 00 00 00 00 04 cb cb cb cb cb
>
> ^
> ffff8801b05e6800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8801b05e6880: 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2
> ==================================================================
>
>
> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report.
> If you forgot to add the Reported-by tag, once the fix for this bug is
> merged
> into any tree, please reply to this email with:
> #syz fix: exact-commit-title
> If you want to test a patch for this bug, please reply with:
> #syz test: git://repo/address.git branch
> and provide the patch inline or as an attachment.
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new bug
> report.
> Note: all commands must start from beginning of the line in the email body.
>
> --
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: alloca-out-of-bounds Read in unwind_next_frame
2018-04-06 0:02 KASAN: alloca-out-of-bounds Read in unwind_next_frame syzbot
2018-04-06 9:09 ` Dmitry Vyukov
@ 2018-04-06 15:36 ` Josh Poimboeuf
2018-04-06 15:40 ` Dmitry Vyukov
1 sibling, 1 reply; 6+ messages in thread
From: Josh Poimboeuf @ 2018-04-06 15:36 UTC (permalink / raw)
To: syzbot
Cc: hpa, linux-kernel, mhiramat, mingo, syzkaller-bugs, tglx, x86, syzkaller
On Thu, Apr 05, 2018 at 05:02:02PM -0700, syzbot wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 06dd3dfeea60e2a6457a6aedf97afc8e6d2ba497 (Thu Apr 5 03:07:20 2018 +0000)
> Merge tag 'char-misc-4.17-rc1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=9d1d9866b0b8ee6e0a8c
>
> syzkaller reproducer:
> https://syzkaller.appspot.com/x/repro.syz?id=6478299081474048
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=5324218015154176
> Kernel config: https://syzkaller.appspot.com/x/.config?id=216543573824217049
> compiler: gcc (GCC) 8.0.1 20180301 (experimental)
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9d1d9866b0b8ee6e0a8c@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
> ==================================================================
> BUG: KASAN: alloca-out-of-bounds in __read_once_size
> include/linux/compiler.h:188 [inline]
> BUG: KASAN: alloca-out-of-bounds in unwind_next_frame.part.7+0x7ce/0x9c0
> arch/x86/kernel/unwind_frame.c:326
> Read of size 8 at addr ffff8801b05e67f8 by task syz-executor2/11326
This looks like a KASAN bug.
The FP unwinder was unwinding from an interrupt which hit while running
in kasan_unpoison_shadow():
> RIP: 0010:kasan_unpoison_shadow+0x1/0x50 mm/kasan/kasan.c:68
> RSP: 0018:ffff8801b05e67e8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
> RAX: ffff8801c1b24100 RBX: 0000000000000000 RCX: ffffffff859d4219
> RDX: 0000000000000000 RSI: 00000000000000a8 RDI: ffff8801b05e6760
> RBP: ffff8801b05e67f8 R08: ffff8801c1b24100 R09: ffffed003b6046c2
> R10: ffffed003b6046c2 R11: ffff8801db023613 R12: 0000000000000015
> R13: 0000000000000001 R14: 0000000000000016 R15: dffffc0000000000
So at first glance it seemed like a race condition. However, the
unwinder was only trying to dereference the frame pointer (RBP:
ffff8801b05e67f8), which should have never been poisoned in the first
place.
So it looks like a bug in the KASAN alloca poisoning.
--
Josh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: alloca-out-of-bounds Read in unwind_next_frame
2018-04-06 15:36 ` Josh Poimboeuf
@ 2018-04-06 15:40 ` Dmitry Vyukov
2018-04-06 16:53 ` Josh Poimboeuf
0 siblings, 1 reply; 6+ messages in thread
From: Dmitry Vyukov @ 2018-04-06 15:40 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: syzbot, H. Peter Anvin, LKML, Masami Hiramatsu, Ingo Molnar,
syzkaller-bugs, Thomas Gleixner, the arch/x86 maintainers,
syzkaller
On Fri, Apr 6, 2018 at 5:36 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Thu, Apr 05, 2018 at 05:02:02PM -0700, syzbot wrote:
>> Hello,
>>
>> syzbot hit the following crash on upstream commit
>> 06dd3dfeea60e2a6457a6aedf97afc8e6d2ba497 (Thu Apr 5 03:07:20 2018 +0000)
>> Merge tag 'char-misc-4.17-rc1' of
>> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
>> syzbot dashboard link:
>> https://syzkaller.appspot.com/bug?extid=9d1d9866b0b8ee6e0a8c
>>
>> syzkaller reproducer:
>> https://syzkaller.appspot.com/x/repro.syz?id=6478299081474048
>> Raw console output:
>> https://syzkaller.appspot.com/x/log.txt?id=5324218015154176
>> Kernel config: https://syzkaller.appspot.com/x/.config?id=216543573824217049
>> compiler: gcc (GCC) 8.0.1 20180301 (experimental)
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+9d1d9866b0b8ee6e0a8c@syzkaller.appspotmail.com
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>>
>> ==================================================================
>> BUG: KASAN: alloca-out-of-bounds in __read_once_size
>> include/linux/compiler.h:188 [inline]
>> BUG: KASAN: alloca-out-of-bounds in unwind_next_frame.part.7+0x7ce/0x9c0
>> arch/x86/kernel/unwind_frame.c:326
>> Read of size 8 at addr ffff8801b05e67f8 by task syz-executor2/11326
>
> This looks like a KASAN bug.
>
> The FP unwinder was unwinding from an interrupt which hit while running
> in kasan_unpoison_shadow():
>
>> RIP: 0010:kasan_unpoison_shadow+0x1/0x50 mm/kasan/kasan.c:68
>> RSP: 0018:ffff8801b05e67e8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
>> RAX: ffff8801c1b24100 RBX: 0000000000000000 RCX: ffffffff859d4219
>> RDX: 0000000000000000 RSI: 00000000000000a8 RDI: ffff8801b05e6760
>> RBP: ffff8801b05e67f8 R08: ffff8801c1b24100 R09: ffffed003b6046c2
>> R10: ffffed003b6046c2 R11: ffff8801db023613 R12: 0000000000000015
>> R13: 0000000000000001 R14: 0000000000000016 R15: dffffc0000000000
>
> So at first glance it seemed like a race condition. However, the
> unwinder was only trying to dereference the frame pointer (RBP:
> ffff8801b05e67f8), which should have never been poisoned in the first
> place.
>
> So it looks like a bug in the KASAN alloca poisoning.
Hi Josh,
You seen my previous message, right? Or was it lost somehow?
https://groups.google.com/d/msg/syzkaller-bugs/IcKqxHzhmQc/KAL6o7tOCAAJ
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: alloca-out-of-bounds Read in unwind_next_frame
2018-04-06 15:40 ` Dmitry Vyukov
@ 2018-04-06 16:53 ` Josh Poimboeuf
2018-04-13 11:16 ` Dmitry Vyukov
0 siblings, 1 reply; 6+ messages in thread
From: Josh Poimboeuf @ 2018-04-06 16:53 UTC (permalink / raw)
To: Dmitry Vyukov
Cc: syzbot, H. Peter Anvin, LKML, Masami Hiramatsu, Ingo Molnar,
syzkaller-bugs, Thomas Gleixner, the arch/x86 maintainers,
syzkaller
On Fri, Apr 06, 2018 at 05:40:01PM +0200, Dmitry Vyukov wrote:
> > So at first glance it seemed like a race condition. However, the
> > unwinder was only trying to dereference the frame pointer (RBP:
> > ffff8801b05e67f8), which should have never been poisoned in the first
> > place.
> >
> > So it looks like a bug in the KASAN alloca poisoning.
>
> Hi Josh,
>
> You seen my previous message, right? Or was it lost somehow?
>
> https://groups.google.com/d/msg/syzkaller-bugs/IcKqxHzhmQc/KAL6o7tOCAAJ
Oops, you're right, I missed it. Seems like we came to the same
conclusion anyway :-)
--
Josh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: alloca-out-of-bounds Read in unwind_next_frame
2018-04-06 16:53 ` Josh Poimboeuf
@ 2018-04-13 11:16 ` Dmitry Vyukov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2018-04-13 11:16 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: syzbot, H. Peter Anvin, LKML, Masami Hiramatsu, Ingo Molnar,
syzkaller-bugs, Thomas Gleixner, the arch/x86 maintainers,
syzkaller
On Fri, Apr 6, 2018 at 6:53 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Fri, Apr 06, 2018 at 05:40:01PM +0200, Dmitry Vyukov wrote:
>> > So at first glance it seemed like a race condition. However, the
>> > unwinder was only trying to dereference the frame pointer (RBP:
>> > ffff8801b05e67f8), which should have never been poisoned in the first
>> > place.
>> >
>> > So it looks like a bug in the KASAN alloca poisoning.
>>
>> Hi Josh,
>>
>> You seen my previous message, right? Or was it lost somehow?
>>
>> https://groups.google.com/d/msg/syzkaller-bugs/IcKqxHzhmQc/KAL6o7tOCAAJ
>
> Oops, you're right, I missed it. Seems like we came to the same
> conclusion anyway :-)
The gcc bug is now fixed
#syz invalid
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-04-13 11:16 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-06 0:02 KASAN: alloca-out-of-bounds Read in unwind_next_frame syzbot
2018-04-06 9:09 ` Dmitry Vyukov
2018-04-06 15:36 ` Josh Poimboeuf
2018-04-06 15:40 ` Dmitry Vyukov
2018-04-06 16:53 ` Josh Poimboeuf
2018-04-13 11:16 ` Dmitry Vyukov
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