bisecting fixing commit since 85a90500f9a1717c4e142ce92e6c1cb1a339ec78 building syzkaller on 6972b10616d785401dea17cec890cca8916424a7 testing commit 85a90500f9a1717c4e142ce92e6c1cb1a339ec78 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 28e193c7fb8e5bc75a6610a308753542ba2a1f2a48fb880f80232176e5ea956d all runs: crashed: possible deadlock in fuse_reverse_inval_entry testing current HEAD 626bf91a292e2035af5b9d9cce35c5c138dfe06d testing commit 626bf91a292e2035af5b9d9cce35c5c138dfe06d compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 5cd5d05076abf6c400fd82913f90a67109f3b371e28abf1f48c87307ee19ed92 run #0: crashed: possible deadlock in fuse_reverse_inval_entry run #1: crashed: possible deadlock in fuse_reverse_inval_entry run #2: crashed: possible deadlock in fuse_reverse_inval_entry run #3: crashed: possible deadlock in fuse_reverse_inval_entry run #4: crashed: possible deadlock in fuse_reverse_inval_entry run #5: crashed: possible deadlock in fuse_reverse_inval_entry run #6: crashed: possible deadlock in fuse_reverse_inval_entry run #7: crashed: possible deadlock in fuse_reverse_inval_entry run #8: crashed: possible deadlock in fuse_reverse_inval_entry run #9: boot failed: KFENCE: use-after-free in kvm_fastop_exception revisions tested: 2, total time: 30m21.754280952s (build: 15m35.762020795s, test: 14m10.947188862s) the crash still happens on HEAD commit msg: Merge tag 'net-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net crash: possible deadlock in fuse_reverse_inval_entry ============================================ WARNING: possible recursive locking detected 5.14.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/10953 is trying to acquire lock: ffff888061028ed0 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline] ffff888061028ed0 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: fuse_reverse_inval_entry+0x1a4/0x480 fs/fuse/dir.c:1093 but task is already holding lock: ffff888061028150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline] ffff888061028150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: fuse_reverse_inval_entry+0x36/0x480 fs/fuse/dir.c:1074 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&type->i_mutex_dir_key#8); lock(&type->i_mutex_dir_key#8); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor.0/10953: #0: ffff888026ed5338 (&fc->killsb){.+.+}-{3:3}, at: fuse_notify_delete fs/fuse/dev.c:1540 [inline] #0: ffff888026ed5338 (&fc->killsb){.+.+}-{3:3}, at: fuse_notify fs/fuse/dev.c:1790 [inline] #0: ffff888026ed5338 (&fc->killsb){.+.+}-{3:3}, at: fuse_dev_do_write+0x1f0a/0x2580 fs/fuse/dev.c:1865 #1: ffff888061028150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline] #1: ffff888061028150 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: fuse_reverse_inval_entry+0x36/0x480 fs/fuse/dir.c:1074 stack backtrace: CPU: 1 PID: 10953 Comm: syz-executor.0 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:105 print_deadlock_bug kernel/locking/lockdep.c:2944 [inline] check_deadlock kernel/locking/lockdep.c:2987 [inline] validate_chain kernel/locking/lockdep.c:3776 [inline] __lock_acquire.cold+0x229/0x3ab kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 down_write+0x92/0x150 kernel/locking/rwsem.c:1515 inode_lock include/linux/fs.h:786 [inline] fuse_reverse_inval_entry+0x1a4/0x480 fs/fuse/dir.c:1093 fuse_notify_delete fs/fuse/dev.c:1541 [inline] fuse_notify fs/fuse/dev.c:1790 [inline] fuse_dev_do_write+0x1f2a/0x2580 fs/fuse/dev.c:1865 fuse_dev_write+0x123/0x1b0 fs/fuse/dev.c:1949 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write+0x360/0x600 fs/read_write.c:507 vfs_write+0x60b/0x900 fs/read_write.c:594 ksys_write+0xf4/0x1d0 fs/read_write.c:647 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: 0033:0x4665e9 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:00007f7bba04b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 000000000000002e RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007fff00a5c45f R14: 00007f7bba04b300 R15: 0000000000022000