syzbot


general protection fault in bfs_get_block

Status: auto-obsoleted due to no activity on 2023/07/13 12:29
Subsystems: bfs
[Documentation on labels]
Reported-by: syzbot+9851c0a26f6143fb0173@syzkaller.appspotmail.com
First crash: 472d, last: 431d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bfs?] general protection fault in bfs_get_block 0 (1) 2023/02/07 17:51
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 general protection fault in bfs_get_block origin:upstream C 1 5d18h 414d 0/3 upstream: reported C repro on 2023/04/02 00:46
upstream general protection fault in bfs_get_block (2) bfs C error done 2 157d 176d 26/26 fixed on 2024/01/30 15:47

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 1 PID: 21540 Comm: syz-executor.2 Not tainted 6.3.0-rc2-syzkaller-00047-g6015b1aca1a2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:bfs_move_block fs/bfs/file.c:42 [inline]
RIP: 0010:bfs_move_blocks fs/bfs/file.c:56 [inline]
RIP: 0010:bfs_get_block+0x35a/0xdd0 fs/bfs/file.c:125
Code: 48 89 f8 48 c1 e8 03 80 3c 08 00 0f 85 64 08 00 00 49 8d 7e 28 48 8b 55 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 2d 08 00 00 48 8d 7d 28 4d 8b 4e 28 48 b9 00 00
RSP: 0018:ffffc900035cef68 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000021 RCX: dffffc0000000000
RDX: 0000000000000200 RSI: ffffffff81f20dff RDI: 0000000000000028
RBP: ffff88807124f950 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000fffffffa R11: 0000000000000000 R12: ffff88804b574000
R13: ffffed10096ae82c R14: 0000000000000000 R15: 0000000000000024
FS:  00007f08ede92700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555591e848 CR3: 000000002d709000 CR4: 00000000003506e0
DR0: 00000000ffff070c DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __block_write_begin_int+0x3bd/0x14b0 fs/buffer.c:2034
 __block_write_begin fs/buffer.c:2084 [inline]
 block_write_begin+0xb9/0x4d0 fs/buffer.c:2145
 bfs_write_begin+0x31/0xd0 fs/bfs/file.c:177
 generic_perform_write+0x256/0x570 mm/filemap.c:3926
 __generic_file_write_iter+0x2ae/0x500 mm/filemap.c:4054
 generic_file_write_iter+0xe3/0x350 mm/filemap.c:4086
 __kernel_write_iter+0x262/0x7a0 fs/read_write.c:517
 __kernel_write+0xcb/0x110 fs/read_write.c:537
 __dump_emit fs/coredump.c:811 [inline]
 dump_emit+0x21d/0x340 fs/coredump.c:848
 writenote+0x206/0x2b0 fs/binfmt_elf.c:1487
 write_note_info fs/binfmt_elf.c:1965 [inline]
 elf_core_dump+0x245c/0x36e0 fs/binfmt_elf.c:2129
 do_coredump+0x2d28/0x3cc0 fs/coredump.c:762
 get_signal+0x1bff/0x25b0 kernel/signal.c:2845
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:309
 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564
RIP: 0033:0x7f08ed08c101
Code: c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 48 3d 01 f0 ff ff 73 01 <c3> 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:0000000020000060 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f08ed1ac050 RCX: 00007f08ed08c0f9
RDX: 0000000020000080 RSI: 0000000020000060 RDI: 0000000000000000
RBP: 00007f08ed0e7b39 R08: 0000000020000280 R09: 0000000020000280
R10: 0000000020000240 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdb1fd5fcf R14: 00007f08ede92300 R15: 0000000000022000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bfs_move_block fs/bfs/file.c:42 [inline]
RIP: 0010:bfs_move_blocks fs/bfs/file.c:56 [inline]
RIP: 0010:bfs_get_block+0x35a/0xdd0 fs/bfs/file.c:125
Code: 48 89 f8 48 c1 e8 03 80 3c 08 00 0f 85 64 08 00 00 49 8d 7e 28 48 8b 55 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 2d 08 00 00 48 8d 7d 28 4d 8b 4e 28 48 b9 00 00
RSP: 0018:ffffc900035cef68 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000021 RCX: dffffc0000000000
RDX: 0000000000000200 RSI: ffffffff81f20dff RDI: 0000000000000028
RBP: ffff88807124f950 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000fffffffa R11: 0000000000000000 R12: ffff88804b574000
R13: ffffed10096ae82c R14: 0000000000000000 R15: 0000000000000024
FS:  00007f08ede92700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08edcd56be CR3: 000000002d709000 CR4: 00000000003506f0
DR0: 00000000ffff070c DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 89 f8             	mov    %rdi,%rax
   3:	48 c1 e8 03          	shr    $0x3,%rax
   7:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1)
   b:	0f 85 64 08 00 00    	jne    0x875
  11:	49 8d 7e 28          	lea    0x28(%r14),%rdi
  15:	48 8b 55 20          	mov    0x20(%rbp),%rdx
  19:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  20:	fc ff df
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	0f 85 2d 08 00 00    	jne    0x861
  34:	48 8d 7d 28          	lea    0x28(%rbp),%rdi
  38:	4d 8b 4e 28          	mov    0x28(%r14),%r9
  3c:	48                   	rex.W
  3d:	b9                   	.byte 0xb9

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/15 12:28 upstream 6015b1aca1a2 18b58603 .config console log report info ci-upstream-kasan-gce-selinux-root general protection fault in bfs_get_block
2023/02/02 01:41 upstream c0b67534c95c 9dfcf09c .config console log report info ci-upstream-kasan-gce-selinux-root general protection fault in bfs_get_block
* Struck through repros no longer work on HEAD.