====================================================== WARNING: possible circular locking dependency detected 4.14.198-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/12932 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:2712 [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_execveat fs/exec.c:1858 [inline] SYSC_execveat fs/exec.c:1939 [inline] SyS_execveat+0x51/0x70 fs/exec.c:1931 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_stack+0x13f/0x2f0 fs/proc/base.c:457 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 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 -> #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.5/12932: #0: (sb_writers#3){.+.+}, at: [] file_start_write include/linux/fs.h:2712 [inline] #0: (sb_writers#3){.+.+}, at: [] do_sendfile+0x84f/0xb30 fs/read_write.c:1440 stack backtrace: CPU: 0 PID: 12932 Comm: syz-executor.5 Not tainted 4.14.198-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: 0033:0x45e179 RSP: 002b:00007f2ea3523c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000027a40 RCX: 000000000045e179 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 4000000000010046 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd1b4d7d9f R14: 00007f2ea35249c0 R15: 000000000118cf4c EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue audit: type=1804 audit(1600974093.388:62): pid=12986 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/87/file0" dev="sda1" ino=16148 res=1 audit: type=1804 audit(1600974093.418:63): pid=12986 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/87/file0" dev="sda1" ino=16148 res=1 audit: type=1804 audit(1600974094.068:64): pid=13019 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/88/file0" dev="sda1" ino=16162 res=1 audit: type=1804 audit(1600974094.098:65): pid=13019 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/88/file0" dev="sda1" ino=16162 res=1 EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue audit: type=1804 audit(1600974094.498:66): pid=13101 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/89/file0" dev="sda1" ino=16150 res=1 audit: type=1804 audit(1600974094.538:67): pid=13101 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/89/file0" dev="sda1" ino=16150 res=1 EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue audit: type=1804 audit(1600974094.818:68): pid=13148 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/90/file0" dev="sda1" ino=16165 res=1 audit: type=1804 audit(1600974094.858:69): pid=13148 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/90/file0" dev="sda1" ino=16165 res=1 EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue audit: type=1804 audit(1600974095.128:70): pid=13200 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/91/file0" dev="sda1" ino=16151 res=1 EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue audit: type=1804 audit(1600974095.168:71): pid=13200 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/91/file0" dev="sda1" ino=16151 res=1 EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue tc_ctl_action: received NO action attribs tc_ctl_action: received NO action attribs EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue tc_ctl_action: received NO action attribs EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue print_req_error: I/O error, dev loop3, sector 0 print_req_error: I/O error, dev loop3, sector 0 print_req_error: I/O error, dev loop3, sector 0 EXT4-fs (loop3): bad geometry: block count 512 exceeds size of device (128 blocks) EXT4-fs (loop3): bad geometry: block count 512 exceeds size of device (128 blocks) EXT4-fs (loop3): bad geometry: block count 512 exceeds size of device (128 blocks) EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 kauditd_printk_skb: 24 callbacks suppressed audit: type=1804 audit(1600974098.398:96): pid=13869 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/103/file0" dev="sda1" ino=16213 res=1 audit: type=1804 audit(1600974098.438:97): pid=13869 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/103/file0" dev="sda1" ino=16213 res=1 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 print_req_error: I/O error, dev loop3, sector 24 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 audit: type=1804 audit(1600974098.698:98): pid=13937 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/104/file0" dev="sda1" ino=16200 res=1 audit: type=1804 audit(1600974098.748:99): pid=13937 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/104/file0" dev="sda1" ino=16200 res=1 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 print_req_error: I/O error, dev loop3, sector 0 audit: type=1804 audit(1600974098.998:100): pid=14007 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/105/file0" dev="sda1" ino=16212 res=1 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 audit: type=1804 audit(1600974099.298:101): pid=14071 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/106/file0" dev="sda1" ino=16210 res=1 print_req_error: I/O error, dev loop3, sector 24 print_req_error: I/O error, dev loop3, sector 0 EXT4-fs warning (device loop3): read_mmp_block:110: Error -117 while reading MMP block 64 audit: type=1804 audit(1600974099.618:102): pid=14138 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/107/file0" dev="sda1" ino=16187 res=1 EXT4-fs warning (device loop3): ext4_multi_mount_protect:325: MMP startup interrupted, failing mount audit: type=1804 audit(1600974100.448:103): pid=14196 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/108/file0" dev="sda1" ino=15864 res=1 audit: type=1804 audit(1600974100.478:104): pid=14196 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/108/file0" dev="sda1" ino=15864 res=1 audit: type=1804 audit(1600974100.538:105): pid=14218 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir869904309/syzkaller.xpkWsa/109/file0" dev="sda1" ino=16221 res=1 EXT4-fs warning (device loop3): ext4_multi_mount_protect:325: MMP startup interrupted, failing mount EXT4-fs warning (device loop3): ext4_multi_mount_protect:325: MMP startup interrupted, failing mount