Comment # 3 on bug 1173891 from Jiri Slaby

FWIW decoded stacktrace is below. The kernel seems to be
a1775d0843b12327f00c719acc05a8224f9ef596.

> BUG: kernel NULL pointer dereference, address: 0000000d
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> *pde = 00000000
> Oops: 0000 [#1] SMP
> CPU: 1 PID: 13684 Comm: rpm Not tainted 5.7.5-1-default #1 openSUSE Tumbleweed (unreleased)
> Hardware name: Dell Inc. Latitude 2100                   /0W785N, BIOS A01 06/02/2009
> EIP: __vfs_write (include/linux/fs.h:3420)
> Code: 00 00 8b 73 24 89 55 b0 89 4d b4 89 f0 89 75 ac c1 e8 09 83 e0 02 81 e6 00 40 00 00 0f 85 fd 00 00 00 8b b3 a4 00 00 00 8b 36 <f6> 46 0d 20 0f 85 eb 00 00 00 f7 45 ac 00 10 00 00 75 15 8b b3 a4
> All code
> ========
>    0: 00 00                   add    %al,(%rax)
>    2: 8b 73 24                mov    0x24(%rbx),%esi
>    5: 89 55 b0                mov    %edx,-0x50(%rbp)
>    8: 89 4d b4                mov    %ecx,-0x4c(%rbp)
>    b: 89 f0                   mov    %esi,%eax
>    d: 89 75 ac                mov    %esi,-0x54(%rbp)
>   10: c1 e8 09                shr    $0x9,%eax
>   13: 83 e0 02                and    $0x2,%eax
>   16: 81 e6 00 40 00 00       and    $0x4000,%esi
>   1c: 0f 85 fd 00 00 00       jne    0x11f
>   22: 8b b3 a4 00 00 00       mov    0xa4(%rbx),%esi
>   28: 8b 36                   mov    (%rsi),%esi
>   2a:*        f6 46 0d 20             testb  $0x20,0xd(%rsi)          <-- trapping instruction
>   2e: 0f 85 eb 00 00 00       jne    0x11f
>   34: f7 45 ac 00 10 00 00    testl  $0x1000,-0x54(%rbp)
>   3b: 75 15                   jne    0x52
>   3d: 8b                      .byte 0x8b
>   3e: b3 a4                   mov    $0xa4,%bl
>
> Code starting with the faulting instruction
> ===========================================
>    0: f6 46 0d 20             testb  $0x20,0xd(%rsi)
>    4: 0f 85 eb 00 00 00       jne    0xf5
>    a: f7 45 ac 00 10 00 00    testl  $0x1000,-0x54(%rbp)
>   11: 75 15                   jne    0x28
>   13: 8b                      .byte 0x8b
>   14: b3 a4                   mov    $0xa4,%bl
> EAX: 00000000 EBX: ddb3a180 ECX: 00005e44 EDX: bfd3af6c
> ESI: 00000000 EDI: c28fdf7c EBP: c28fdf4c ESP: c28fdef4
> DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246
> CR0: 80050033 CR2: 0000000d CR3: 32744000 CR4: 000006d0
> Call Trace:
> vfs_write (fs/read_write.c:560)
> ksys_write (fs/read_write.c:613)
> __ia32_sys_write (fs/read_write.c:621)
> do_int80_syscall_32 (arch/x86/entry/common.c:337)
> entry_INT80_32 (arch/x86/entry/entry_32.S:1085)