====================================================== WARNING: possible circular locking dependency detected 4.19.128-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/16474 is trying to acquire lock: 00000000744fabe8 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 but task is already holding lock: 00000000acf29f59 (&p->lock){+.+.}, at: seq_read+0x6b/0x10c0 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/0x10c0 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+0x477/0x970 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+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_do_remove+0xf8/0xd70 fs/overlayfs/dir.c:843 vfs_rmdir fs/namei.c:3882 [inline] vfs_rmdir+0x18b/0x450 fs/namei.c:3861 do_rmdir+0x371/0x3e0 fs/namei.c:3943 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]#2){++++}: inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x1a04/0x2eb0 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+0x18d6/0x20c0 fs/exec.c:1757 do_execveat_common fs/exec.c:1866 [inline] do_execve+0x2e/0x40 fs/exec.c:1883 __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x7c/0xa0 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 do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10c0 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#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 *** 1 lock held by syz-executor.3/16474: #0: 00000000acf29f59 (&p->lock){+.+.}, at: seq_read+0x6b/0x10c0 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 16474 Comm: syz-executor.3 Not tainted 4.19.128-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/0x2fe lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x3145/0x4380 kernel/locking/lockdep.c:3415 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10c0 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: 0033:0x45ca69 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc05dfadc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000004faf40 RCX: 000000000045ca69 RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000879 R14: 00000000004cb665 R15: 00007fc05dfae6d4 overlayfs: option "workdir=./" is useless in a non-upper mount, ignore overlayfs: unrecognized mount option "w8orkdir=./file1" or missing value overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "ÿÿÿÿÿÿÿÿ" or missing value overlayfs: unrecognized mount option "ÿÿÿÿÿÿÿÿ" or missing value overlayfs: unrecognized mount option "w8orkdir=./file1" or missing value 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: failed to resolve './file^': -2 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "pperdir=./file0B" or missing value overlayfs: unrecognized mount option "pperdir=./file0B" or missing value overlayfs: failed to resolve './file0øË ­ªD(': -2 overlayfs: failed to resolve './file0øË ­ªD(': -2 overlayfs: missing 'lowerdir' overlayfs: unrecognized mount option "0xffffffffffffffff18446744073709551615ÿÿ" or missing value overlayfs: missing 'lowerdir' EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: unrecognized mount option "" or missing value EXT4-fs (loop5): Invalid log block size: 65 overlayfs: missing 'lowerdir' overlayfs: unrecognized mount option "" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "lowes" or missing value overlayfs: unrecognized mount option "up" or missing value overlayfs: unrecognized mount option "lowes" or missing value overlayfs: unrecognized mount option "up" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: unrecognized mount option "lower " or missing value EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "lower " or missing value overlayfs: unrecognized mount option "upperdi=./file0" or missing value overlayfs: unrecognized mount option "lower" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "upperdi=./file0" or missing value overlayfs: unrecognized mount option "lowrdir=B/bus" or missing value overlayfs: unrecognized mount option "wor#ú„ kdpperdir=./™±ê÷“Ä[nIÈî/*ëeÖ«ÿSŸÍÄ!Ùè–÷äQÏ<”&iXZ ³dNgÿ’šš|ãÿ7î‘8lMµösñž•Í‘ä_nëƯ³]»ON]" or missing value overlayfs: unrecognized mount option "wor#ú„ kdpperdir=./™±ê÷“Ä[nIÈî/*ëeÖ«ÿSŸÍÄ!Ùè–÷äQÏ<”&iXZ ³dNgÿ’šš|ãÿ7î‘8lMµösñž•Í‘ä_nëƯ³]»ON]" or missing value overlayfs: workdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: failed to resolve './file0': -2 EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: unrecognized mount option "01777777777777777777777" or missing value EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "worodir=./file1" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: unrecognized mount option "subj_role=" or missing value EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: option "workdir=./fiÇç*WØÖ rdir=./file08y8Å5_¯=ˆ e•Ö(Òt¨cá•{Y¤" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./fiÇç*WØÖ rdir=./file08y8Å5_¯=ˆ e•Ö(Òt¨cá•{Y¤" is useless in a non-upper mount, ignore overlayfs: option "workdir=./filee0" 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=./filee0" is useless in a non-upper mount, ignore EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: failed to resolve './file0': -2 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "lowB›úr./bus" or missing value overlayfs: unrecognized mount option "lw’Ë ±@—rdir=jÚvŒõ_ ./bus" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: unrecognized mount option "lowB›úr./bus" or missing value EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: failed to resolve './file0ØÈÚ ¾Îx/¸‰Š/tÀÛDI·kd¹v¤Êc*Ý': -2 EXT4-fs (loop5): Invalid log block size: 65 overlayfs: failed to resolve './file0ØÈÚ ¾Îx/¸‰Š/tÀÛDI·kd¹v¤Êc*Ý': -2 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "l±ª(ÿowerdir=./bus" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: unrecognized mount option "l±ª(ÿowerdir=./bus" or missing value EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem overlayfs: failed to resolve './file0': -2 EXT4-fs (loop5): Invalid log block size: 65 overlayfs: failed to resolve './file0': -2 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 EXT4-fs (loop5): mounting ext2 file system using the ext4 subsystem EXT4-fs (loop5): Invalid log block size: 65 overlayfs: failed to resolve '