====================================================== WARNING: possible circular locking dependency detected 5.10.96 #1 Not tainted ------------------------------------------------------ syz-executor.3/9892 is trying to acquire lock: ffff888043c1e758 (&sig->exec_update_lock){++++}-{3:3}, at: lock_trace fs/proc/base.c:408 [inline] ffff888043c1e758 (&sig->exec_update_lock){++++}-{3:3}, at: proc_pid_syscall+0xa8/0x2b0 fs/proc/base.c:646 but task is already holding lock: ffff88804aa6bc30 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xdf/0x12b0 fs/seq_file.c:182 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&p->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13f/0x1250 kernel/locking/mutex.c:1109 seq_read_iter+0xdf/0x12b0 fs/seq_file.c:182 kernfs_fop_read_iter+0x452/0x5f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:1897 [inline] io_iter_do_read+0x87/0x120 fs/io_uring.c:3406 io_read+0x244/0xe00 fs/io_uring.c:3449 io_issue_sqe+0xe5c/0x3c40 fs/io_uring.c:6027 __io_queue_sqe+0x204/0xd00 fs/io_uring.c:6354 io_queue_sqe+0x5bc/0x1020 fs/io_uring.c:6420 io_submit_sqe fs/io_uring.c:6489 [inline] io_submit_sqes+0x130d/0x2310 fs/io_uring.c:6717 __do_sys_io_uring_enter+0x1086/0x1900 fs/io_uring.c:9113 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&ctx->uring_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13f/0x1250 kernel/locking/mutex.c:1109 io_disable_sqo_submit+0x1f/0x230 fs/io_uring.c:8731 io_uring_flush+0x2a1/0x590 fs/io_uring.c:8950 filp_close+0xb7/0x170 fs/open.c:1288 do_close_on_exec+0x1ec/0x360 fs/file.c:811 begin_new_exec+0x106f/0x2a10 fs/exec.c:1311 load_elf_binary+0x7e1/0x4c60 fs/binfmt_elf.c:998 search_binary_handler fs/exec.c:1703 [inline] exec_binprm fs/exec.c:1744 [inline] bprm_execve+0x9bd/0x1b00 fs/exec.c:1820 do_execveat_common+0x621/0x7c0 fs/exec.c:1915 do_execveat fs/exec.c:1994 [inline] __do_sys_execveat fs/exec.c:2070 [inline] __se_sys_execveat fs/exec.c:2062 [inline] __x64_sys_execveat+0xed/0x130 fs/exec.c:2062 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&sig->exec_update_lock){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 down_read_killable+0x9e/0x460 kernel/locking/rwsem.c:1527 lock_trace fs/proc/base.c:408 [inline] proc_pid_syscall+0xa8/0x2b0 fs/proc/base.c:646 proc_single_show+0x121/0x1f0 fs/proc/base.c:775 seq_read_iter+0x50c/0x12b0 fs/seq_file.c:230 seq_read+0x3dd/0x5b0 fs/seq_file.c:162 do_loop_readv_writev fs/read_write.c:761 [inline] do_loop_readv_writev fs/read_write.c:748 [inline] do_iter_read+0x484/0x6d0 fs/read_write.c:803 vfs_readv+0xe5/0x150 fs/read_write.c:921 do_preadv fs/read_write.c:1013 [inline] __do_sys_preadv fs/read_write.c:1063 [inline] __se_sys_preadv fs/read_write.c:1058 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1058 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &sig->exec_update_lock --> &ctx->uring_lock --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(&ctx->uring_lock); lock(&p->lock); lock(&sig->exec_update_lock); *** DEADLOCK *** 1 lock held by syz-executor.3/9892: #0: ffff88804aa6bc30 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xdf/0x12b0 fs/seq_file.c:182 stack backtrace: CPU: 1 PID: 9892 Comm: syz-executor.3 Not tainted 5.10.96 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2121 check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 down_read_killable+0x9e/0x460 kernel/locking/rwsem.c:1527 lock_trace fs/proc/base.c:408 [inline] proc_pid_syscall+0xa8/0x2b0 fs/proc/base.c:646 proc_single_show+0x121/0x1f0 fs/proc/base.c:775 seq_read_iter+0x50c/0x12b0 fs/seq_file.c:230 seq_read+0x3dd/0x5b0 fs/seq_file.c:162 do_loop_readv_writev fs/read_write.c:761 [inline] do_loop_readv_writev fs/read_write.c:748 [inline] do_iter_read+0x484/0x6d0 fs/read_write.c:803 vfs_readv+0xe5/0x150 fs/read_write.c:921 do_preadv fs/read_write.c:1013 [inline] __do_sys_preadv fs/read_write.c:1063 [inline] __se_sys_preadv fs/read_write.c:1058 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1058 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fa2fa634b19 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa2f7baa188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007fa2fa747f60 RCX: 00007fa2fa634b19 RDX: 0000000000000001 RSI: 0000000020000080 RDI: 0000000000000004 RBP: 00007fa2fa68ef6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd5e4d79bf R14: 00007fa2f7baa300 R15: 0000000000022000 EXT4-fs warning (device sda): verify_group_input:152: Reserved blocks too high (1)