syz-executor.4 (18810): drop_caches: 2 ====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/18818 is trying to acquire lock: 000000001b3fb573 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2750 [inline] 000000001b3fb573 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 but task is already holding lock: 000000006d390589 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x11c0 fs/seq_file.c:164 proc_reg_read+0x1bd/0x2d0 fs/proc/inode.c:231 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:602 lookup_open+0x893/0x1a20 fs/namei.c:3235 do_last fs/namei.c:3327 [inline] path_openat+0x1094/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x17ec/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_open_execat+0x11d/0x5b0 fs/exec.c:853 __do_execve_file+0x1a8b/0x2360 fs/exec.c:1770 do_execveat_common fs/exec.c:1879 [inline] do_execve+0x35/0x50 fs/exec.c:1896 __do_sys_execve fs/exec.c:1977 [inline] __se_sys_execve fs/exec.c:1972 [inline] __x64_sys_execve+0x7c/0xa0 fs/exec.c:1972 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 2 locks held by syz-executor.3/18818: #0: 0000000021e0ab46 (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 0000000021e0ab46 (sb_writers#4){.+.+}, at: do_sendfile+0x97d/0xc30 fs/read_write.c:1446 #1: 000000006d390589 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 1 PID: 18818 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 fs/splice.c:417 syz-executor.1 (18792): drop_caches: 2 syz-executor.1 (18792): drop_caches: 2 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 syz-executor.2 (18794): drop_caches: 2 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f6b5dbe1059 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6b5c556168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f6b5dcf3f60 RCX: 00007f6b5dbe1059 syz-executor.4 (18825): drop_caches: 2 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007f6b5dc3b08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe04ea603f R14: 00007f6b5c556300 R15: 0000000000022000 syz-executor.1 (18831): drop_caches: 2 syz-executor.4 (18855): drop_caches: 1 syz-executor.1 (18865): drop_caches: 2 syz-executor.4 (18888): drop_caches: 2 syz-executor.1 (18857): drop_caches: 2 syz-executor.1 (18857): drop_caches: 2 syz-executor.1 (18954): drop_caches: 2 syz-executor.3 (18959): drop_caches: 2 syz-executor.3 (18975): drop_caches: 2 syz-executor.4 (18974): drop_caches: 2 syz-executor.1 (18982): drop_caches: 2 syz-executor.2 (18984): drop_caches: 2 syz-executor.1 (19009): drop_caches: 2 syz-executor.3 (19005): drop_caches: 2 syz-executor.4 (19017): drop_caches: 2 syz-executor.2 (19041): drop_caches: 2 syz-executor.3 (19044): drop_caches: 2 syz-executor.2 (19067): drop_caches: 2 syz-executor.3 (19091): drop_caches: 2 syz-executor.2 (19101): drop_caches: 2 syz-executor.4 (19054): drop_caches: 2 syz-executor.2 (19118): drop_caches: 1 syz-executor.3 (19130): drop_caches: 2 syz-executor.4 (19148): drop_caches: 2 syz-executor.2 (19149): drop_caches: 2 syz-executor.4 (19129): drop_caches: 1 syz-executor.4 (19129): drop_caches: 1 syz-executor.1 (19161): drop_caches: 2 syz-executor.4 (19117): drop_caches: 1 syz-executor.3 (19193): drop_caches: 2 syz-executor.4 (19117): drop_caches: 2 syz-executor.1 (19159): drop_caches: 2 syz-executor.1 (19159): drop_caches: 2 syz-executor.2 (19162): drop_caches: 1 syz-executor.4 (19238): drop_caches: 2 syz-executor.4 (19230): drop_caches: 1 syz-executor.1 (19234): drop_caches: 1 syz-executor.3 (19294): drop_caches: 2 syz-executor.4 (19230): drop_caches: 1 syz-executor.1 (19298): drop_caches: 2 syz-executor.2 (19243): drop_caches: 2 syz-executor.4 (19206): drop_caches: 2 syz-executor.4 (19206): drop_caches: 2 syz-executor.4 (19317): drop_caches: 2 syz-executor.1 (19297): drop_caches: 2 syz-executor.3 (19335): drop_caches: 2 syz-executor.1 (19297): drop_caches: 2 syz-executor.4 (19316): drop_caches: 2 syz-executor.4 (19316): drop_caches: 2 syz-executor.3 (19343): drop_caches: 2 syz-executor.1 (19342): drop_caches: 2 syz-executor.1 (19350): drop_caches: 2 syz-executor.3 (19348): drop_caches: 2 syz-executor.3 (19356): drop_caches: 2 syz-executor.4 (19313): drop_caches: 2 syz-executor.4 (19313): drop_caches: 2 syz-executor.2 (19314): drop_caches: 2 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 syz-executor.4 (19403): drop_caches: 2 syz-executor.4 (19428): drop_caches: 2 syz-executor.4 (19441): drop_caches: 2 syz-executor.1 (19409): drop_caches: 2 syz-executor.1 (19409): drop_caches: 2 syz-executor.2 (19470): drop_caches: 2 syz-executor.4 (19517): drop_caches: 2 syz-executor.1 (19479): drop_caches: 2 syz-executor.1 (19479): drop_caches: 2 syz-executor.3 (19531): drop_caches: 2 syz-executor.4 (19537): drop_caches: 2 syz-executor.3 (19572): drop_caches: 2 syz-executor.4 (19568): drop_caches: 2 syz-executor.3 (19580): drop_caches: 2 syz-executor.3 (19588): drop_caches: 2 syz-executor.1 (19559): drop_caches: 2 syz-executor.1 (19559): drop_caches: 2 syz-executor.4 (19603): drop_caches: 2 syz-executor.3 (19599): drop_caches: 2 syz-executor.2 (19579): drop_caches: 2 device lo entered promiscuous mode syz-executor.4 (19591): drop_caches: 2 syz-executor.4 (19591): drop_caches: 2 syz-executor.4 (19640): drop_caches: 2 syz-executor.3 (19670): drop_caches: 2 Y4`Ҙ: renamed from lo syz-executor.2 (19642): drop_caches: 2 syz-executor.3 (19698): drop_caches: 2 syz-executor.3 (19739): drop_caches: 2 syz-executor.1 (19715): drop_caches: 2 syz-executor.3 (19739): drop_caches: 2