====================================================== WARNING: possible circular locking dependency detected 4.14.194-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/8315 is trying to acquire lock: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1120 fs/seq_file.c:165 but task is already holding lock: (sb_writers#3){.+.+}, at: [] file_start_write include/linux/fs.h:2708 [inline] (sb_writers#3){.+.+}, at: [] do_sendfile+0x84f/0xb30 fs/read_write.c:1440 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (sb_writers#3){.+.+}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x19a/0x2e0 fs/super.c:1363 sb_start_write include/linux/fs.h:1549 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538 lookup_open+0x77a/0x1750 fs/namei.c:3241 do_last fs/namei.c:3334 [inline] path_openat+0xe08/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (&ovl_i_mutex_dir_key[depth]){++++}: down_read+0x36/0x80 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x149b/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_open_execat+0xd3/0x450 fs/exec.c:849 do_execveat_common+0x711/0x1f30 fs/exec.c:1742 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x3b/0x50 fs/exec.c:1923 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 lock_trace fs/proc/base.c:407 [inline] proc_pid_syscall+0xa7/0x2a0 fs/proc/base.c:639 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4cf/0x1120 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 do_preadv fs/read_write.c:1065 [inline] SYSC_preadv fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 fs/read_write.c:1110 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&p->lock){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1120 fs/seq_file.c:165 proc_reg_read+0xee/0x1a0 fs/proc/inode.c:217 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x418/0x910 fs/splice.c:416 do_splice_to+0xfb/0x140 fs/splice.c:880 splice_direct_to_actor+0x207/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &p->lock --> &ovl_i_mutex_dir_key[depth] --> sb_writers#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#3); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#3); lock(&p->lock); *** DEADLOCK *** 1 lock held by syz-executor.0/8315: #0: (sb_writers#3){.+.+}, at: [] file_start_write include/linux/fs.h:2708 [inline] #0: (sb_writers#3){.+.+}, at: [] do_sendfile+0x84f/0xb30 fs/read_write.c:1440 stack backtrace: CPU: 0 PID: 8315 Comm: syz-executor.0 Not tainted 4.14.194-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1120 fs/seq_file.c:165 proc_reg_read+0xee/0x1a0 fs/proc/inode.c:217 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x418/0x910 fs/splice.c:416 do_splice_to+0xfb/0x140 fs/splice.c:880 splice_direct_to_actor+0x207/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45d579 RSP: 002b:00007ff6ea850c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000027840 RCX: 000000000045d579 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 4000000000010046 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd6e65c0bf R14: 00007ff6ea8519c0 R15: 000000000118cf4c overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 kauditd_printk_skb: 16 callbacks suppressed audit: type=1804 audit(1598349530.895:5353): pid=8426 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1405/bus/bus" dev="sda1" ino=15913 res=1 audit: type=1804 audit(1598349531.685:5354): pid=8458 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1406/bus/bus" dev="sda1" ino=16054 res=1 audit: type=1804 audit(1598349531.785:5355): pid=8473 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1407/bus/bus" dev="sda1" ino=16011 res=1 audit: type=1804 audit(1598349531.885:5356): pid=8480 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1408/bus/bus" dev="sda1" ino=16002 res=1 audit: type=1804 audit(1598349531.955:5357): pid=8488 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1409/bus/bus" dev="sda1" ino=16040 res=1 overlayfs: missing 'lowerdir' audit: type=1804 audit(1598349532.215:5358): pid=8516 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1410/bus/bus" dev="sda1" ino=15840 res=1 overlayfs: missing 'lowerdir' audit: type=1804 audit(1598349532.345:5359): pid=8527 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1411/bus/bus" dev="sda1" ino=15993 res=1 overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' audit: type=1804 audit(1598349532.505:5360): pid=8534 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1412/bus/bus" dev="sda1" ino=16055 res=1 overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' audit: type=1804 audit(1598349532.615:5361): pid=8545 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1413/bus/bus" dev="sda1" ino=16070 res=1 overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' audit: type=1804 audit(1598349532.855:5362): pid=8569 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1414/bus/bus" dev="sda1" ino=16055 res=1 overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "upper" or missing value overlayfs: unrecognized mount option "upper" or missing value overlayfs: unrecognized mount option "upper" or missing value overlayfs: unrecognized mount option "upper" or missing value overlayfs: unrecognized mount option "upper" or missing value overlayfs: unrecognized mount option "upper" or missing value overlayfs: workdir and upperdir must be separate subtrees overlayfs: workdir and upperdir must be separate subtrees overlayfs: workdir and upperdir must be separate subtrees overlayfs: workdir and upperdir must be separate subtrees overlayfs: workdir and upperdir must be separate subtrees overlayfs: failed to resolve './fil': -2 overlayfs: failed to resolve './fil': -2 overlayfs: workdir and upperdir must be separate subtrees overlayfs: failed to resolve './fil': -2 overlayfs: failed to resolve './fil': -2 overlayfs: failed to resolve './file': -2 overlayfs: failed to resolve './fil': -2 overlayfs: failed to resolve './file': -2 overlayfs: failed to resolve './fil': -2 overlayfs: failed to resolve './file': -2 overlayfs: failed to resolve './file': -2 overlayfs: failed to resolve './file': -2 overlayfs: failed to resolve './file': -2 IPVS: length: 205 != 8 kauditd_printk_skb: 20 callbacks suppressed audit: type=1804 audit(1598349536.955:5383): pid=8971 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1443/bus/bus" dev="sda1" ino=15903 res=1 audit: type=1804 audit(1598349537.165:5384): pid=9003 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1444/bus/bus" dev="sda1" ino=16105 res=1 audit: type=1804 audit(1598349537.285:5385): pid=9014 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1445/bus/bus" dev="sda1" ino=16027 res=1 audit: type=1804 audit(1598349537.405:5386): pid=9026 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1446/bus/bus" dev="sda1" ino=16011 res=1 audit: type=1804 audit(1598349537.535:5387): pid=9042 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1447/bus/bus" dev="sda1" ino=15919 res=1 audit: type=1804 audit(1598349537.685:5388): pid=9057 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1448/bus/bus" dev="sda1" ino=16009 res=1 audit: type=1804 audit(1598349537.795:5389): pid=9068 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1449/bus/bus" dev="sda1" ino=15997 res=1 audit: type=1804 audit(1598349537.965:5390): pid=9080 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1450/bus/bus" dev="sda1" ino=15920 res=1 audit: type=1804 audit(1598349538.255:5391): pid=9101 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1451/bus/bus" dev="sda1" ino=15917 res=1 audit: type=1804 audit(1598349538.375:5392): pid=9115 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir499985276/syzkaller.BVaemm/1452/bus/bus" dev="sda1" ino=16073 res=1