====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.8.10474/5674 is trying to acquire lock: ffff8880254ae460 (sb_writers#6){.+.+}-{0:0}, at: lookup_open+0x150/0x1990 fs/namei.c:4451 but task is already holding lock: ffff88802cf27920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&common->filesem){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631 fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&p->frag_sem){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574 __configfs_open_file+0xe8/0x9c0 fs/configfs/file.c:304 do_dentry_open+0x6ab/0x14d0 fs/open.c:996 vfs_open+0x82/0x3f0 fs/open.c:1101 dentry_open+0x71/0xd0 fs/open.c:1124 ima_calc_file_hash+0xe1/0x380 security/integrity/ima/ima_crypto.c:269 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425 ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685 security_file_post_open+0xc4/0x210 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x5cd/0x2440 fs/namei.c:5000 do_file_open+0x20e/0x430 fs/namei.c:5029 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821 process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319 ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685 security_file_post_open+0xc4/0x210 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x5cd/0x2440 fs/namei.c:5000 do_file_open+0x20e/0x430 fs/namei.c:5029 file_open_name+0x1c3/0x3e0 fs/open.c:1375 filp_open+0x2e/0x50 fs/open.c:1392 kernel_read_file_from_path_initns+0xec/0x240 fs/kernel_read_file.c:159 fw_get_filesystem_firmware drivers/base/firmware_loader/main.c:549 [inline] _request_firmware+0x733/0x13c0 drivers/base/firmware_loader/main.c:873 request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:948 reg_reload_regdb+0x85/0x460 net/wireless/reg.c:1067 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767 __sys_sendmsg+0x160/0x210 net/socket.c:2799 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (cb_lock){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574 genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] sock_sendmsg+0x394/0x410 net/socket.c:838 splice_to_socket+0xb3c/0x11a0 fs/splice.c:884 do_splice_from fs/splice.c:936 [inline] do_splice+0x109c/0x1fa0 fs/splice.c:1349 __do_splice+0x33b/0x370 fs/splice.c:1431 __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1616 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&pipe->mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821 pipe_lock fs/pipe.c:91 [inline] pipe_lock+0x69/0x80 fs/pipe.c:88 iter_file_splice_write+0x1fd/0x10b0 fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0x109c/0x1fa0 fs/splice.c:1349 __do_splice+0x33b/0x370 fs/splice.c:1431 __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1616 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sb_writers#6){.+.+}-{0:0}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write include/linux/fs/super.h:125 [inline] mnt_want_write+0x6f/0x420 fs/namespace.c:494 lookup_open+0x150/0x1990 fs/namei.c:4451 open_last_lookups fs/namei.c:4767 [inline] path_openat+0xa2c/0x2440 fs/namei.c:4997 do_file_open+0x20e/0x430 fs/namei.c:5029 file_open_name+0x1c3/0x3e0 fs/open.c:1375 filp_open+0x2e/0x50 fs/open.c:1392 fsg_lun_open+0x6b/0x7b0 drivers/usb/gadget/function/storage_common.c:194 fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: sb_writers#6 --> &p->frag_sem --> &common->filesem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&common->filesem); lock(&p->frag_sem); lock(&common->filesem); rlock(sb_writers#6); *** DEADLOCK *** locks held by syz.8.10474/5674: 5, last CPU#2: #0: ffff8880384dc630 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff88801fed8460 (sb_writers#16){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff8880408c4280 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4e0 fs/configfs/file.c:226 #3: ffff88803da36170 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] #3: ffff88803da36170 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229 #4: ffff88802cf27920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452 stack backtrace: CPU: 2 UID: 0 PID: 5674 Comm: syz.8.10474 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write include/linux/fs/super.h:125 [inline] mnt_want_write+0x6f/0x420 fs/namespace.c:494 lookup_open+0x150/0x1990 fs/namei.c:4451 open_last_lookups fs/namei.c:4767 [inline] path_openat+0xa2c/0x2440 fs/namei.c:4997 do_file_open+0x20e/0x430 fs/namei.c:5029 file_open_name+0x1c3/0x3e0 fs/open.c:1375 filp_open+0x2e/0x50 fs/open.c:1392 fsg_lun_open+0x6b/0x7b0 drivers/usb/gadget/function/storage_common.c:194 fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4bea59e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4beb3bf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4bea825fa0 RCX: 00007f4bea59e159 RDX: 0000000000000005 RSI: 00002000000003c0 RDI: 0000000000000003 RBP: 00007f4bea635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4bea826038 R14: 00007f4bea825fa0 R15: 00007fff8dcc5478 mass_storage.0/lun.0: unable to open backing file: file0