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2002:a05:6808:2e4d:b0:4e7:978b:ad91 with SMTP id 5614622812f47-50c57695625mr13025422b6e.49.1791930145279; Tue, 13 Oct 2026 15:22:25 -0700 (PDT) Date: Tue, 13 Oct 2026 15:22:25 -0700 In-Reply-To: <6a6aad2e.57649fcc.360844.000d.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aceaf21.8cdf6287.1eb53.0174.GAE@google.com> Subject: Re: [syzbot] [integrity?] [lsm?] possible deadlock in __configfs_open_file (2) From: syzbot To: a.hindborg@kernel.org, leitao@debian.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 24a19b953e2a Linux 7.3-rc7 git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=165f3c35580000 kernel config: https://syzkaller.appspot.com/x/.config?x=129d675874dbf896 dashboard link: https://syzkaller.appspot.com/bug?extid=c87014f645f2fd24312e compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10cf93d1580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c87014f645f2fd24312e@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor387/5997 is trying to acquire lock: ffff888035be1570 (&p->frag_sem){.+.+}-{4:4}, at: __configfs_open_file+0xe8/0x9c0 fs/configfs/file.c:304 but task is already holding lock: ffffffff91d84848 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (cb_lock){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 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:1338 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1919 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 -> #2 (&pipe->mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 fifo_open+0x139/0xb40 fs/pipe.c:1235 do_dentry_open+0x6ab/0x14d0 fs/open.c:996 vfs_open+0x82/0x3f0 fs/open.c:1101 do_open fs/namei.c:4866 [inline] path_openat+0x19fa/0x2440 fs/namei.c:5029 do_file_open+0x20e/0x430 fs/namei.c:5058 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 -> #1 (&common->filesem){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631 fsg_store_file+0x264/0x450 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 -> #0 (&p->frag_sem){.+.+}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209 check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 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 do_open fs/namei.c:4866 [inline] path_openat+0x19fa/0x2440 fs/namei.c:5029 do_file_open+0x20e/0x430 fs/namei.c:5058 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:2575 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1919 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 other info that might help us debug this: Chain exists of: &p->frag_sem --> &pipe->mutex --> cb_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(cb_lock); lock(&pipe->mutex); lock(cb_lock); rlock(&p->frag_sem); *** DEADLOCK *** locks held by syz-executor387/5997: 2, last CPU#0: #0: ffff888035fc7860 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] #0: ffff888035fc7860 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x69/0x80 fs/pipe.c:88 #1: ffffffff91d84848 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 stack backtrace: CPU: 0 UID: 0 PID: 5997 Comm: syz-executor387 Not tainted syzkaller #0 PREEMPT(full) 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:2087 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209 check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 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 do_open fs/namei.c:4866 [inline] path_openat+0x19fa/0x2440 fs/namei.c:5029 do_file_open+0x20e/0x430 fs/namei.c:5058 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:2575 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1919 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 RIP: 0033:0x7f7180644b5e Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08 RSP: 002b:00007f717cde6f18 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f717cde76c0 RCX: 00007f7180644b5e RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 00007f717cde6fe0 R08: 0000000000000014 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000012 R13: 00007f717cde6f80 R14: 000000000000017e R15: 0000000000000010 faux_driver regulatory: loading /lib/firmware/regulatory.db failed with error -26 faux_driver regulatory: Direct firmware load for regulatory.db failed with error -26 faux_driver regulatory: Falling back to sysfs fallback for: regulatory.db --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.