5.4-stable review patch. If anyone has any objections, please let me know.
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From: Edward Adam Davis eadavis@qq.com
[ Upstream commit d73dc7b182be4238b75278bfae16afb4c5564a58 ]
[Syzbot reported two possible deadlocks] The first possible deadlock is: WARNING: possible recursive locking detected 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted -------------------------------------------- syz-executor363/2651 is trying to acquire lock: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x15d/0x2c0 drivers/usb/misc/chaoskey.c:322
but task is already holding lock: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x7f/0x2c0 drivers/usb/misc/chaoskey.c:299
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ---- lock(chaoskey_list_lock); lock(chaoskey_list_lock);
*** DEADLOCK ***
The second possible deadlock is: WARNING: possible circular locking dependency detected 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted ------------------------------------------------------ kworker/0:2/804 is trying to acquire lock: ffffffff899dadb0 (minor_rwsem){++++}-{3:3}, at: usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186
but task is already holding lock: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (chaoskey_list_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 chaoskey_open+0xdd/0x220 drivers/usb/misc/chaoskey.c:274 usb_open+0x186/0x220 drivers/usb/core/file.c:47 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6cb/0x1390 fs/open.c:958 vfs_open+0x82/0x3f0 fs/open.c:1088 do_open fs/namei.c:3774 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3933 do_filp_open+0x1dc/0x430 fs/namei.c:3960 do_sys_openat2+0x17a/0x1e0 fs/open.c:1415 do_sys_open fs/open.c:1430 [inline] __do_sys_openat fs/open.c:1446 [inline] __se_sys_openat fs/open.c:1441 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1441 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (minor_rwsem){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 down_write+0x93/0x200 kernel/locking/rwsem.c:1577 usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186 chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236 usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:569 [inline] device_remove+0x122/0x170 drivers/base/dd.c:561 __device_release_driver drivers/base/dd.c:1273 [inline] device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296 bus_remove_device+0x22f/0x420 drivers/base/bus.c:576 device_del+0x396/0x9f0 drivers/base/core.c:3864 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418 usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304 hub_port_connect drivers/usb/core/hub.c:5361 [inline] hub_port_connect_change drivers/usb/core/hub.c:5661 [inline] port_event drivers/usb/core/hub.c:5821 [inline] hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(chaoskey_list_lock); lock(minor_rwsem); lock(chaoskey_list_lock); lock(minor_rwsem);
*** DEADLOCK *** [Analysis] The first is AA lock, it because wrong logic, it need a unlock. The second is AB lock, it needs to rearrange the order of lock usage.
Fixes: 422dc0a4d12d ("USB: chaoskey: fail open after removal") Reported-by: syzbot+685e14d04fe35692d3bc@syzkaller.appspotmail.com Reported-by: syzbot+1f8ca5ee82576ec01f12@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=685e14d04fe35692d3bc Signed-off-by: Edward Adam Davis eadavis@qq.com Tested-by: syzbot+685e14d04fe35692d3bc@syzkaller.appspotmail.com Reported-by: syzbot+5f1ce62e956b7b19610e@syzkaller.appspotmail.com Tested-by: syzbot+5f1ce62e956b7b19610e@syzkaller.appspotmail.com Tested-by: syzbot+1f8ca5ee82576ec01f12@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/tencent_84EB865C89862EC22EE94CB3A7C706C59206@qq.co... Cc: Oliver Neukum oneukum@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/misc/chaoskey.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c index 32fa7fd50c380..d99d424c05a7a 100644 --- a/drivers/usb/misc/chaoskey.c +++ b/drivers/usb/misc/chaoskey.c @@ -233,10 +233,10 @@ static void chaoskey_disconnect(struct usb_interface *interface) if (dev->hwrng_registered) hwrng_unregister(&dev->hwrng);
- mutex_lock(&chaoskey_list_lock); usb_deregister_dev(interface, &chaoskey_class);
usb_set_intfdata(interface, NULL); + mutex_lock(&chaoskey_list_lock); mutex_lock(&dev->lock);
dev->present = false; @@ -320,7 +320,7 @@ static int chaoskey_release(struct inode *inode, struct file *file) bail: mutex_unlock(&dev->lock); destruction: - mutex_lock(&chaoskey_list_lock); + mutex_unlock(&chaoskey_list_lock); usb_dbg(interface, "release success"); return rv; }