During our functional tests, we have ran into the following issue for i686:
[ 19.301067] BUG: unable to handle kernel NULL pointer dereference at 0000028a
which might have triggered false positive for:
[ 48.544348] BUG: sleeping function called from invalid context at
/srv/oe/build/tmp-rpb-glibc/work-shared/intel-core2-32/kernel-source/include/linux/percpu-rwsem.h:34
For latest 4.20.0-rc1-next-20181107, when running fsync01 LTP test in
this kernel.
----
[ 19.120300] BUG: unable to handle kernel NULL pointer dereference at 0000028a
[ 19.127433] *pde = 00000000
[ 19.130311] Oops: 0000 [#1] SMP
[ 19.133449] CPU: 2 PID: 2557 Comm: ata_id Not tainted
4.20.0-rc1-next-20181107 #1
[ 19.140920] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 19.148391] EIP: locks_remove_flock+0x60/0xb0
[ 19.152749] Code: 10 e8 b4 d3 ff ff 8b 43 14 83 4d 80 40 8b 70 58
85 f6 74 46 8d 8d 58 ff ff ff ba 07 00 00 00 89 d8 ff d6 8b 45 d8 85
c0 74 0f <8b> 50 04 85 d2 74 08 8d 85 58 ff ff ff ff d2 8b 45 f0 65 33
05 14
[ 19.171484] EAX: 00000286 EBX: f501c140 ECX: 00000000 EDX: ffffffff
[ 19.177742] ESI: 00000000 EDI: f53978c8 EBP: f37dff14 ESP: f37dfe6c
[ 19.183999] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010202
[ 19.190776] CR0: 80050033 CR2: 0000028a CR3: 343f9000 CR4: 003406d0
[ 19.197035] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 19.203299] DR6: fffe0ff0 DR7: 00000400
[ 19.207152] Call Trace:
[ 19.209604] ? lockdep_hardirqs_on+0xe4/0x190
[ 19.213961] ? ktime_get_coarse_real_ts64+0x4d/0xd0
[ 19.218838] ? trace_hardirqs_on+0x43/0xe0
[ 19.222930] ? __audit_syscall_entry+0xb2/0xf0
[ 19.227375] locks_remove_file+0x3e/0x1e0
[ 19.231380] __fput+0xc2/0x1f0
[ 19.234440] ____fput+0xd/0x10
[ 19.237499] task_work_run+0x7f/0xb0
[ 19.241078] exit_to_usermode_loop+0x9d/0xa0
[ 19.245349] do_fast_syscall_32+0x257/0x2a0
[ 19.249527] entry_SYSENTER_32+0x70/0xc8
[ 19.253444] EIP: 0xb7ee9991
[ 19.256234] Code: 8b 98 60 cd ff ff 85 d2 89 c8 74 02 89 0a 5b 5d
c3 8b 04 24 c3 8b 14 24 c3 8b 1c 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f
34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90
8d 76
[ 19.274971] EAX: 00000000 EBX: 00000004 ECX: 00000043 EDX: b7e9a894
[ 19.281228] ESI: b7eb8000 EDI: 00000016 EBP: b7ccc6b0 ESP: bf9c7830
[ 19.287485] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000246
[ 19.294263] Modules linked in: fuse
[ 19.297754] CR2: 000000000000028a
[ 19.301066] ---[ end trace 30875d5239ac018c ]---
And, with EIP: locks_remove_flock+0x60/0xb0, we have:
c12777c0 <locks_remove_flock>:
c12777c0: e8 eb 26 dd ff call c1049eb0 <__fentry__>
c12777c5: 55 push %ebp
c12777c6: 83 c2 20 add $0x20,%edx
c12777c9: 89 e5 mov %esp,%ebp
c12777cb: 57 push %edi
c12777cc: 56 push %esi
c12777cd: 53 push %ebx
c12777ce: 89 c3 mov %eax,%ebx
c12777d0: 81 ec 9c 00 00 00 sub $0x9c,%esp
c12777d6: 65 a1 14 00 00 00 mov %gs:0x14,%eax
c12777dc: 89 45 f0 mov %eax,-0x10(%ebp)
c12777df: 31 c0 xor %eax,%eax
c12777e1: 8b 02 mov (%edx),%eax
c12777e3: 39 c2 cmp %eax,%edx
c12777e5: 74 48 je c127782f
<locks_remove_flock+0x6f>
c12777e7: 8d 8d 58 ff ff ff lea -0xa8(%ebp),%ecx
c12777ed: ba 08 00 00 00 mov $0x8,%edx
c12777f2: 89 d8 mov %ebx,%eax
c12777f4: 8b 7b 10 mov 0x10(%ebx),%edi
c12777f7: e8 b4 d3 ff ff call c1274bb0 <flock_make_lock>
c12777fc: 8b 43 14 mov 0x14(%ebx),%eax
-------------- EIP
c12777ff: 83 4d 80 40 orl $0x40,-0x80(%ebp)
c1277803: 8b 70 58 mov 0x58(%eax),%esi
c1277806: 85 f6 test %esi,%esi
----
Pointing to:
locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
{
struct file_lock fl;
...
flock_make_lock(filp, LOCK_UN, &fl);
...
}
Since flock_make_lock() calls locks_alloc_lock() and kmem_cache_zalloc()...
shouldn't "fl" be declared as *fl pointer ?
----
Link: https://bugs.linaro.org/show_bug.cgi?id=4056
Full dmesg: https://lkft.validation.linaro.org/scheduler/job/497741#L964
