Re: [syzbot] [bfs?] general protection fault in bfs_get_block (3)

[syzbot <syzbot+f51a2a34984e4d8888fd@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in mark_buffer_dirty

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6436 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520 fs/buffer.c:1177
Modules linked in:
CPU: 0 UID: 0 PID: 6436 Comm: syz.0.76 Not tainted 6.12.0-rc5-syzkaller-00299-g11066801dd4b-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:mark_buffer_dirty+0x2e5/0x520 fs/buffer.c:1177
Code: 89 df e8 fe 82 db ff 48 8b 3b be 20 00 00 00 5b 41 5e 41 5f 5d e9 fb e8 fb ff e8 26 c4 71 ff e9 73 ff ff ff e8 1c c4 71 ff 90 <0f> 0b 90 e9 61 fd ff ff e8 0e c4 71 ff 90 0f 0b 90 e9 88 fd ff ff
RSP: 0018:ffffc9000d30eb50 EFLAGS: 00010293
RAX: ffffffff82231604 RBX: ffff8880459fea01 RCX: ffff88803d044880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff82231361 R09: 1ffff11003542579
R10: dffffc0000000000 R11: ffffed100354257a R12: 000000000000000a
R13: dffffc0000000000 R14: ffff88801aa12bc8 R15: ffff88804553b200
FS:  00007fda86b986c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0fe3329fe4 CR3: 000000004a36e000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bfs_move_block fs/bfs/file.c:47 [inline]
 bfs_move_blocks fs/bfs/file.c:60 [inline]
 bfs_get_block+0x8be/0xb40 fs/bfs/file.c:129
 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2121
 block_write_begin+0x8f/0x120 fs/buffer.c:2231
 bfs_write_begin+0x35/0xd0 fs/bfs/file.c:182
 generic_perform_write+0x344/0x6d0 mm/filemap.c:4054
 generic_file_write_iter+0xae/0x310 mm/filemap.c:4181
 __kernel_write_iter+0x42a/0x940 fs/read_write.c:616
 __kernel_write+0x120/0x180 fs/read_write.c:636
 __dump_emit+0x237/0x360 fs/coredump.c:807
 writenote+0x221/0x3b0 fs/binfmt_elf.c:1463
 write_note_info fs/binfmt_elf.c:1941 [inline]
 elf_core_dump+0x37ba/0x4770 fs/binfmt_elf.c:2108
 do_coredump+0x2162/0x2ec0 fs/coredump.c:758
 get_signal+0x13fc/0x1740 kernel/signal.c:2902
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x79/0x280 kernel/entry/common.c:231
 exc_page_fault+0x590/0x8c0 arch/x86/mm/fault.c:1542
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fda85d7e721
Code: 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:ffffffffffffffe0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fda85f36058 RCX: 00007fda85d7e719
RDX: 0000000000000000 RSI: ffffffffffffffe0 RDI: 0000000004008011
RBP: 00007fda85df132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fda85f36058 R15: 00007ffe98382878
 </TASK>


Tested on:

commit:         11066801 Merge tag 'linux_kselftest-fixes-6.12-rc6' of..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12280d5f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4aec7739e14231a7
dashboard link: https://syzkaller.appspot.com/bug?extid=f51a2a34984e4d8888fd
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=152e6987980000