syzbot


BUG: unable to handle kernel NULL pointer dereference in wakeup_flusher_threads

Status: closed as invalid on 2018/02/13 20:04
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+828cc6faaec36fad920e9025c3b56932cfe980ff@syzkaller.appspotmail.com
First crash: 2786d, last: 2786d

Sample crash report:
QAT: Invalid ioctl
QAT: Invalid ioctl
BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
IP: __read_once_size include/linux/compiler.h:183 [inline]
IP: atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
IP: atomic_long_read include/asm-generic/atomic-long.h:45 [inline]
IP: bdi_has_dirty_io include/linux/backing-dev.h:62 [inline]
IP: __wakeup_flusher_threads_bdi fs/fs-writeback.c:1979 [inline]
IP: wakeup_flusher_threads+0xdb/0x1f0 fs/fs-writeback.c:2009
QAT: Invalid ioctl
PGD 1fb546067 P4D 1fb546067 PUD 1f9ff0067 PMD 0 
Oops: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 11953 Comm: syz-executor4 Not tainted 4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
RIP: 0010:atomic_long_read include/asm-generic/atomic-long.h:45 [inline]
RIP: 0010:bdi_has_dirty_io include/linux/backing-dev.h:62 [inline]
RIP: 0010:__wakeup_flusher_threads_bdi fs/fs-writeback.c:1979 [inline]
RIP: 0010:wakeup_flusher_threads+0xdb/0x1f0 fs/fs-writeback.c:2009
RSP: 0018:ffffc90000f2ff20 EFLAGS: 00010212
RAX: 0000000000010000 RBX: 0000000000000000 RCX: ffffffff8145287b
RDX: 00000000000001db RSI: ffffc90004739000 RDI: ffff8801fca78300
RBP: ffffc90000f2ff30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: 00000000ffffffff R14: 00007f88002d36d4 R15: 0000000000000000
FS:  00007f88002d3700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000050 CR3: 00000001f9d32002 CR4: 00000000001626e0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 sys_sync+0x25/0xa0 fs/sync.c:112
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f88002d2c58 EFLAGS: 00000212 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000000015f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ef188
R13: 00000000ffffffff R14: 00007f88002d36d4 R15: 0000000000000000
Code: 7a e6 ff 48 8b 1d b6 72 c4 01 48 81 fb 10 9b 09 83 75 13 eb 31 e8 d6 7a e6 ff 48 8b 1b 48 81 fb 10 9b 09 83 74 20 e8 c5 7a e6 ff <48> 8b 43 50 48 85 c0 74 e1 e8 b7 7a e6 ff 44 89 e6 48 89 df e8 
RIP: __read_once_size include/linux/compiler.h:183 [inline] RSP: ffffc90000f2ff20
RIP: atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline] RSP: ffffc90000f2ff20
RIP: atomic_long_read include/asm-generic/atomic-long.h:45 [inline] RSP: ffffc90000f2ff20
RIP: bdi_has_dirty_io include/linux/backing-dev.h:62 [inline] RSP: ffffc90000f2ff20
RIP: __wakeup_flusher_threads_bdi fs/fs-writeback.c:1979 [inline] RSP: ffffc90000f2ff20
RIP: wakeup_flusher_threads+0xdb/0x1f0 fs/fs-writeback.c:2009 RSP: ffffc90000f2ff20
CR2: 0000000000000050
---[ end trace 71acdba8a9c19486 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2017/12/19 15:48 linux-next 6084b576dca2 af9163c7 .config console log report ci-upstream-next-kasan-gce
* Struck through repros no longer work on HEAD.