BUG: stack guard page was hit in fixup_exception

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 42f82040 Merge tag 'drm-fixes-2020-07-10' of git://anongit..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12d80333100000
kernel config: https://syzkaller.appspot.com/x/.config?x=66ad203c2bb6d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=3370f8260246b965fefd
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3370f8...@syzkaller.appspotmail.com

BUG: stack guard page was hit at 000000004cbdbd91 (stack is 00000000e7fa34ab..000000001a32f95e)
kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 11649 Comm: kworker/u4:5 Not tainted 5.8.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:fixup_exception+0x0/0xca arch/x86/mm/extable.c:143
Code: 5d 41 5c c3 e8 b1 9f 3f 00 45 31 e4 5b 44 89 e0 5d 41 5c c3 48 89 ef e8 9e f8 7e 00 eb c7 66 90 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 49 89 cf 41 56 49 89 d6 41 55 41 89 f5 41 54 49 89 fc 55 53
RSP: 0018:ffffc90001810000 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffffc900018102a0 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 000000000000000e RDI: ffffc90001810218
RBP: ffffc90001810218 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000000000b R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000180fff8 CR3: 000000008749d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc900018102c8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc900018105d0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc900018105f8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc90001810900 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc90001810928 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc90001810c30 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc90001810c58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc90001810f60 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc90001810f88 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc90001811290 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc900018112b8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffc900018115c0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83968d3b RDI: 0000000000000001
RBP: ffffffff810078f7 R08: ffffffff83ad6dc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000000e R14: 0000000000000002 R15: 0000000000000000
search_module_extables+0xce/0x100 kernel/module.c:4425
search_exception_tables+0x42/0x50 kernel/extable.c:59
fixup_exception+0x4b/0xca arch/x86/mm/extable.c:161
no_context+0xe7/0x9f0 arch/x86/mm/fault.c:599
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault+0x783/0xd00 arch/x86/mm/fault.c:1171
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
RIP: 0010:preempt_schedule_thunk+0x0/0x18 arch/x86/entry/thunk_64.S:40
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00
Lost 823 message(s)!
---[ end trace 7175130f674c1b3d ]---
RIP: 0010:fixup_exception+0x0/0xca arch/x86/mm/extable.c:143
Code: 5d 41 5c c3 e8 b1 9f 3f 00 45 31 e4 5b 44 89 e0 5d 41 5c c3 48 89 ef e8 9e f8 7e 00 eb c7 66 90 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 49 89 cf 41 56 49 89 d6 41 55 41 89 f5 41 54 49 89 fc 55 53
RSP: 0018:ffffc90001810000 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffffc900018102a0 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 000000000000000e RDI: ffffc90001810218
RBP: ffffc90001810218 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000000000b R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000180fff8 CR3: 000000008749d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[Andy Lutomirski]

On Sat, Jul 11, 2020 at 12:10 AM syzbot
<syzbot+3370f8...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 42f82040 Merge tag 'drm-fixes-2020-07-10' of git://anongit..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12d80333100000
> kernel config: https://syzkaller.appspot.com/x/.config?x=66ad203c2bb6d8b
> dashboard link: https://syzkaller.appspot.com/bug?extid=3370f8260246b965fefd
> compiler: gcc (GCC) 10.1.0-syz 20200507
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+3370f8...@syzkaller.appspotmail.com
>

> Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

I bet this is the same fbcon bug.