====================================================== WARNING: possible circular locking dependency detected 4.19.108-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/27808 is trying to acquire lock: 0000000061473172 (&sig->cred_guard_mutex){+.+.}, at: lock_trace+0x45/0xe0 fs/proc/base.c:402 but task is already holding lock: 0000000014abe13a (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x10f0 fs/seq_file.c:161 proc_reg_read+0x1bd/0x280 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+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 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+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 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#4){.+.+}: sb_start_write include/linux/fs.h:1578 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_link+0x73/0x2a5 fs/overlayfs/dir.c:674 vfs_link+0x79f/0xb50 fs/namei.c:4243 do_linkat+0x4ed/0x700 fs/namei.c:4311 __do_sys_link fs/namei.c:4340 [inline] __se_sys_link fs/namei.c:4338 [inline] __x64_sys_link+0x5d/0x80 fs/namei.c:4338 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_key[depth]){+.+.}: inode_lock include/linux/fs.h:747 [inline] process_measurement+0x91f/0x1430 security/integrity/ima/ima_main.c:205 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:391 do_last fs/namei.c:3425 [inline] path_openat+0x1086/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_open_execat+0x124/0x5b0 fs/exec.c:853 __do_execve_file.isra.0+0x1577/0x2110 fs/exec.c:1755 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 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:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 lock_trace+0x45/0xe0 fs/proc/base.c:402 proc_pid_syscall+0x94/0x240 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 do_preadv+0x1b6/0x270 fs/read_write.c:1071 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#4 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#4); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.2/27808: #0: 0000000014abe13a (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 27808 Comm: syz-executor.2 Not tainted 4.19.108-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+0x188/0x20d lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1861 [inline] check_prevs_add kernel/locking/lockdep.c:1974 [inline] validate_chain kernel/locking/lockdep.c:2415 [inline] __lock_acquire+0x2e19/0x49c0 kernel/locking/lockdep.c:3411 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3903 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 lock_trace+0x45/0xe0 fs/proc/base.c:402 proc_pid_syscall+0x94/0x240 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 do_preadv+0x1b6/0x270 fs/read_write.c:1071 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c6c9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3cbe1f3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f3cbe1f46d4 RCX: 000000000045c6c9 RDX: 000000000000037d RSI: 0000000020000500 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000857 R14: 00000000004caff6 R15: 000000000076bf2c BTRFS: device fsid 01f6f2a2-2997-48ae-b81e-1b00b10efd9a devid 0 transid 0 /dev/loop0 netlink: 16 bytes leftover after parsing attributes in process `syz-executor.1'. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. cgroup: fork rejected by pids controller in /syz2 overlayfs: workdir and upperdir must reside under the same mount overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.1'. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.1'. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. kauditd_printk_skb: 205 callbacks suppressed audit: type=1400 audit(1583928473.766:14227): avc: denied { map } for pid=28022 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928473.806:14228): avc: denied { map } for pid=28022 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928473.946:14229): avc: denied { map } for pid=28027 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: conflicting lowerdir path audit: type=1400 audit(1583928474.006:14230): avc: denied { map } for pid=28030 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928474.016:14231): avc: denied { map } for pid=28027 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928474.016:14232): avc: denied { map } for pid=28027 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2251 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928474.196:14233): avc: denied { map } for pid=28037 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 overlayfs: conflicting lowerdir path overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. audit: type=1400 audit(1583928474.236:14234): avc: denied { map } for pid=28037 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2251 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. audit: type=1400 audit(1583928474.246:14235): avc: denied { map } for pid=28037 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 overlayfs: conflicting lowerdir path overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. audit: type=1400 audit(1583928474.256:14236): avc: denied { map } for pid=28037 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 overlayfs: conflicting lowerdir path overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. SELinux: failed to load policy SELinux: failed to load policy SELinux: failed to load policy SELinux: failed to load policy caif:caif_disconnect_client(): nothing to disconnect caif:caif_disconnect_client(): nothing to disconnect kauditd_printk_skb: 203 callbacks suppressed audit: type=1400 audit(1583928478.806:14440): avc: denied { map } for pid=28268 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.846:14441): avc: denied { map } for pid=28268 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.846:14442): avc: denied { map } for pid=28268 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.866:14443): avc: denied { map } for pid=28267 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.876:14444): avc: denied { map } for pid=28267 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.876:14445): avc: denied { map } for pid=28267 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 caif:caif_disconnect_client(): nothing to disconnect audit: type=1400 audit(1583928478.886:14446): avc: denied { map } for pid=28267 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2251 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.926:14447): avc: denied { map } for pid=28267 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928478.926:14448): avc: denied { map } for pid=28272 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1583928479.036:14449): avc: denied { map } for pid=28273 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 caif:caif_disconnect_client(): nothing to disconnect SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=28347 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=28347 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=28347 comm=syz-executor.2