bisecting fixing commit since ad347abe4a9876b1f65f408ab467137e88f77eb4 building syzkaller on 1ba81399e2d03b53a7e631c4ab05f25af1fb1911 testing commit ad347abe4a9876b1f65f408ab467137e88f77eb4 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: c2d8cc2b680573b1fe5880a753a4343e3571c3459ec88ea869c66fc676422b4e all runs: crashed: kernel BUG in ext4_writepages testing current HEAD 0aa78d17099b04fd9d36fe338af48ad6fe2d7fca testing commit 0aa78d17099b04fd9d36fe338af48ad6fe2d7fca compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 976a5fb4cc52799ef92996bbd1a850a4f49c764dbacb01428ae15b386f20c624 all runs: crashed: kernel BUG in ext4_writepages revisions tested: 2, total time: 26m35.901114204s (build: 19m34.298892938s, test: 6m24.529015398s) the crash still happens on HEAD commit msg: Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi crash: kernel BUG in ext4_writepages ------------[ cut here ]------------ kernel BUG at fs/ext4/inode.c:2704! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 10245 Comm: syz-executor.2 Not tainted 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:ext4_writepages+0x1a87/0x2d10 fs/ext4/inode.c:2704 Code: 0f 87 b2 30 32 06 be 00 10 00 00 ba 01 00 00 00 4c 89 e7 48 d3 ee e8 48 66 fe ff 83 c0 01 89 84 24 c8 00 00 00 e9 4b eb ff ff <0f> 0b 89 44 24 08 e9 97 ef ff ff 48 8b 7c 24 28 e8 94 ea b5 ff e9 RSP: 0018:ffffc9000b20f5c8 EFLAGS: 00010247 RAX: 000000c410000000 RBX: ffff88802c5a8000 RCX: ffffffff81f05bc4 RDX: 1ffff11006af93c7 RSI: 0000000000000008 RDI: ffff8880357c9e38 RBP: ffff8880357c9e38 R08: 0000000000000000 R09: ffff8880357c9e3f R10: ffffed1006af93c7 R11: ffff8880357ca560 R12: ffff8880357ca120 R13: ffffc9000b20fa50 R14: 0000000000000001 R15: ffff88802c5a8000 FS: 00007f99917ee700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555d0e7b5e98 CR3: 000000003338e000 CR4: 0000000000350ef0 Call Trace: do_writepages+0xca/0x240 mm/page-writeback.c:2355 __filemap_fdatawrite_range+0x243/0x320 mm/filemap.c:413 file_write_and_wait_range+0x8d/0xf0 mm/filemap.c:792 ext4_sync_file+0x1c8/0xc90 fs/ext4/fsync.c:151 generic_write_sync include/linux/fs.h:2987 [inline] ext4_buffered_write_iter+0x2d3/0x440 fs/ext4/file.c:277 ext4_file_write_iter+0x383/0x1160 fs/ext4/file.c:680 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write+0x35d/0x5f0 fs/read_write.c:518 vfs_write+0x5b1/0x880 fs/read_write.c:605 ksys_write+0xf4/0x1d0 fs/read_write.c:658 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 Code: ff ff c3 66 2e 0f 1f 84 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f99917ee188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000000082 RSI: 0000000020000180 RDI: 0000000000000004 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffcbeab38df R14: 00007f99917ee300 R15: 0000000000022000 Modules linked in: ---[ end trace e3e6313d6bab142f ]--- RIP: 0010:ext4_writepages+0x1a87/0x2d10 fs/ext4/inode.c:2704 Code: 0f 87 b2 30 32 06 be 00 10 00 00 ba 01 00 00 00 4c 89 e7 48 d3 ee e8 48 66 fe ff 83 c0 01 89 84 24 c8 00 00 00 e9 4b eb ff ff <0f> 0b 89 44 24 08 e9 97 ef ff ff 48 8b 7c 24 28 e8 94 ea b5 ff e9 RSP: 0018:ffffc9000b20f5c8 EFLAGS: 00010247 RAX: 000000c410000000 RBX: ffff88802c5a8000 RCX: ffffffff81f05bc4 RDX: 1ffff11006af93c7 RSI: 0000000000000008 RDI: ffff8880357c9e38 RBP: ffff8880357c9e38 R08: 0000000000000000 R09: ffff8880357c9e3f R10: ffffed1006af93c7 R11: ffff8880357ca560 R12: ffff8880357ca120 R13: ffffc9000b20fa50 R14: 0000000000000001 R15: ffff88802c5a8000 FS: 00007f99917ee700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9a1268f010 CR3: 000000003338e000 CR4: 0000000000350ee0 ---------------- Code disassembly (best guess): 0: 0f 87 b2 30 32 06 ja 0x63230b8 6: be 00 10 00 00 mov $0x1000,%esi b: ba 01 00 00 00 mov $0x1,%edx 10: 4c 89 e7 mov %r12,%rdi 13: 48 d3 ee shr %cl,%rsi 16: e8 48 66 fe ff callq 0xfffe6663 1b: 83 c0 01 add $0x1,%eax 1e: 89 84 24 c8 00 00 00 mov %eax,0xc8(%rsp) 25: e9 4b eb ff ff jmpq 0xffffeb75 2a: 0f 0b ud2 <-- trapping instruction 2c: 89 44 24 08 mov %eax,0x8(%rsp) 30: e9 97 ef ff ff jmpq 0xffffefcc 35: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi 3a: e8 94 ea b5 ff callq 0xffb5ead3 3f: e9 .byte 0xe9