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) 2.35.2 kernel signature: 865d3c40c172cafc1eeff01355f98b9738f56605a5dc669616daa8f5df3b4827 all runs: crashed: kernel BUG in ext4_writepages testing current HEAD 0885eacdc81f920c3e0554d5615e69a66504a28d testing commit 0885eacdc81f920c3e0554d5615e69a66504a28d compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 9b9b97bd42500efe46c521ddf59ee06b493e3f8e3cf4f19c21b01b2ac2d88529 run #0: crashed: kernel BUG in ext4_writepages run #1: crashed: kernel BUG in ext4_writepages run #2: crashed: kernel BUG in ext4_writepages run #3: crashed: kernel BUG in ext4_writepages run #4: crashed: kernel BUG in ext4_writepages run #5: crashed: kernel BUG in ext4_writepages run #6: boot failed: INFO: task hung in add_early_randomness run #7: boot failed: INFO: task hung in add_early_randomness run #8: boot failed: INFO: task hung in add_early_randomness run #9: boot failed: INFO: task hung in add_early_randomness revisions tested: 2, total time: 26m47.718498314s (build: 12m47.041531909s, test: 13m17.772261596s) the crash still happens on HEAD commit msg: Merge tag 'nfsd-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux crash: kernel BUG in ext4_writepages EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none. ------------[ cut here ]------------ kernel BUG at fs/ext4/inode.c:2720! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 4126 Comm: syz-executor.0 Not tainted 5.19.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:ext4_writepages+0x1a88/0x2d10 fs/ext4/inode.c:2720 Code: 0f 87 66 92 5e 06 be 00 10 00 00 ba 01 00 00 00 4c 89 e7 48 d3 ee e8 67 67 fe ff 83 c0 01 89 84 24 c8 00 00 00 e9 48 eb ff ff <0f> 0b 89 44 24 08 e9 94 ef ff ff 48 8b 7c 24 28 e8 93 b2 b3 ff e9 RSP: 0018:ffffc90002fff510 EFLAGS: 00010247 RAX: 000000c410000000 RBX: ffff88806c116000 RCX: ffffffff81fb20b2 RDX: 1ffff1100e56000a RSI: 0000000000000008 RDI: ffff888072b00050 RBP: ffff888072b00050 R08: 0000000000000000 R09: ffff888072b00057 R10: ffffed100e56000a R11: 0000000000000000 R12: ffff888072b002b0 R13: ffffc90002fffa58 R14: 0000000000000001 R15: ffff88806c116000 FS: 00007f530402f700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005575f9c6b0d0 CR3: 000000001d692000 CR4: 0000000000350ee0 Call Trace: do_writepages+0x16e/0x5f0 mm/page-writeback.c:2443 filemap_fdatawrite_wbc mm/filemap.c:388 [inline] filemap_fdatawrite_wbc+0x107/0x170 mm/filemap.c:378 __filemap_fdatawrite_range+0xa2/0xe0 mm/filemap.c:421 file_write_and_wait_range+0x8d/0xf0 mm/filemap.c:779 ext4_sync_file+0x1c8/0xc90 fs/ext4/fsync.c:151 generic_write_sync include/linux/fs.h:2731 [inline] ext4_buffered_write_iter+0x201/0x2c0 fs/ext4/file.c:277 ext4_file_write_iter+0x39d/0x11a0 fs/ext4/file.c:679 call_write_iter include/linux/fs.h:2058 [inline] new_sync_write+0x2e0/0x520 fs/read_write.c:504 vfs_write+0x607/0x8f0 fs/read_write.c:591 ksys_write+0xee/0x1c0 fs/read_write.c:644 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 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:00007f530402f188 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: 00007ffc9569789f R14: 00007f530402f300 R15: 0000000000022000 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_writepages+0x1a88/0x2d10 fs/ext4/inode.c:2720 Code: 0f 87 66 92 5e 06 be 00 10 00 00 ba 01 00 00 00 4c 89 e7 48 d3 ee e8 67 67 fe ff 83 c0 01 89 84 24 c8 00 00 00 e9 48 eb ff ff <0f> 0b 89 44 24 08 e9 94 ef ff ff 48 8b 7c 24 28 e8 93 b2 b3 ff e9 RSP: 0018:ffffc90002fff510 EFLAGS: 00010247 RAX: 000000c410000000 RBX: ffff88806c116000 RCX: ffffffff81fb20b2 RDX: 1ffff1100e56000a RSI: 0000000000000008 RDI: ffff888072b00050 RBP: ffff888072b00050 R08: 0000000000000000 R09: ffff888072b00057 R10: ffffed100e56000a R11: 0000000000000000 R12: ffff888072b002b0 R13: ffffc90002fffa58 R14: 0000000000000001 R15: ffff88806c116000 FS: 00007f530402f700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005575f9c6b0d0 CR3: 000000001d692000 CR4: 0000000000350ee0