bisecting fixing commit since 88b06399c9c766c283e070b022b5ceafa4f63f19 building syzkaller on b3c3bb8e115e28ac78d37da1ee8931351d6cb113 testing commit 88b06399c9c766c283e070b022b5ceafa4f63f19 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 6512804c55f2e3e68ebf099b572c030ca24a7c2b037191e210a922412fb14f76 all runs: crashed: WARNING in inc_nlink testing current HEAD ecf93431963a95c0f475921101bedc0dd62ec96d testing commit ecf93431963a95c0f475921101bedc0dd62ec96d compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 3c813c77b005190ce8d62ea2b35bc78cc18220d7c875e190802029bf4ce529b7 all runs: crashed: WARNING in inc_nlink revisions tested: 2, total time: 20m8.687206979s (build: 12m40.498690397s, test: 6m46.836825734s) the crash still happens on HEAD commit msg: Merge tag 'powerpc-5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux crash: WARNING in inc_nlink VFS: Found a V7 FS (block size = 512) on device loop1 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 10176 at fs/inode.c:361 inc_nlink+0x126/0x150 fs/inode.c:365 Modules linked in: CPU: 1 PID: 10176 Comm: syz-executor.1 Not tainted 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:inc_nlink+0x126/0x150 fs/inode.c:361 Code: ef 89 44 24 04 e8 ba 89 f0 ff 8b 44 24 04 e9 4d ff ff ff 48 89 ef e8 39 89 f0 ff e9 14 ff ff ff 48 89 ef e8 2c 89 f0 ff eb cc <0f> 0b e9 6a ff ff ff e8 2e 89 f0 ff e9 53 ff ff ff e8 24 89 f0 ff RSP: 0018:ffffc9000a8f7df0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88803da989d8 RCX: 00000000000000a8 RDX: 1ffff11007b53156 RSI: ffff88803da989d8 RDI: ffff88803da98ab0 RBP: ffff88803da98a20 R08: ffff88803da989f8 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88803da989d8 R13: ffff88803d6ff1b8 R14: 0000000000000000 R15: ffff88803da989d8 FS: 00007f1f782f3700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff9ee9f6010 CR3: 00000000173d8000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: inode_inc_link_count include/linux/fs.h:2433 [inline] sysv_mkdir+0x17/0xf0 fs/sysv/namei.c:119 vfs_mkdir+0x43d/0x6a0 fs/namei.c:3823 do_mkdirat+0x20c/0x280 fs/namei.c:3848 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: 0033:0x4665f9 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:00007f1f782f3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9 RDX: 00000000000000b8 RSI: 0000000020000040 RDI: 0000000000000005 RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe5abb33ef R14: 00007f1f782f3300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: ef out %eax,(%dx) 1: 89 44 24 04 mov %eax,0x4(%rsp) 5: e8 ba 89 f0 ff callq 0xfff089c4 a: 8b 44 24 04 mov 0x4(%rsp),%eax e: e9 4d ff ff ff jmpq 0xffffff60 13: 48 89 ef mov %rbp,%rdi 16: e8 39 89 f0 ff callq 0xfff08954 1b: e9 14 ff ff ff jmpq 0xffffff34 20: 48 89 ef mov %rbp,%rdi 23: e8 2c 89 f0 ff callq 0xfff08954 28: eb cc jmp 0xfffffff6 2a: 0f 0b ud2 <-- trapping instruction 2c: e9 6a ff ff ff jmpq 0xffffff9b 31: e8 2e 89 f0 ff callq 0xfff08964 36: e9 53 ff ff ff jmpq 0xffffff8e 3b: e8 24 89 f0 ff callq 0xfff08964