| Summary: | possible circular locking dependency detected in acm_tty_open vs acm_tty_close | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Mikko Tiihonen <mikko.tiihonen> |
| Component: | kernel | Assignee: | Kernel Maintainer List <kernel-maint> |
| Status: | CLOSED RAWHIDE | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | rawhide | CC: | gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2012-02-02 15:00:25 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
This should be fixed with commit 7fb57a019f94ea0c1290c39b8da753be155af41c |
Description of problem: kernel reports about a possible deadlock Version-Release number of selected component (if applicable): kernel-3.2.0-0.rc7.git0.1.fc17.x86_64 How reproducible: Reported on every boot. Actual results: [ INFO: possible circular locking dependency detected ] 3.2.0-0.rc7.git0.1.fc17.x86_64 #1 ------------------------------------------------------- modem-manager/1122 is trying to acquire lock: (big_tty_mutex){+.+.+.}, at: [<ffffffff81678127>] tty_lock+0x17/0x19 but task is already holding lock: (open_mutex){+.+...}, at: [<ffffffffa055b321>] acm_tty_close+0x41/0xc0 [cdc_acm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (open_mutex){+.+...}: [<ffffffff810bf70d>] lock_acquire+0x9d/0x1f0 [<ffffffff816750e4>] mutex_lock_nested+0x74/0x3a0 [<ffffffffa055b715>] acm_tty_open+0x35/0x230 [cdc_acm] [<ffffffff813b9747>] tty_open+0x247/0x5d0 [<ffffffff811b1d68>] chrdev_open+0xe8/0x320 [<ffffffff811aa494>] __dentry_open+0x3d4/0x500 [<ffffffff811abbe4>] nameidata_to_filp+0x74/0x80 [<ffffffff811bd57c>] do_last+0x26c/0x8f0 [<ffffffff811bdd15>] path_openat+0xd5/0x3e0 [<ffffffff811be142>] do_filp_open+0x42/0xa0 [<ffffffff811abce7>] do_sys_open+0xf7/0x1d0 [<ffffffff811abde0>] sys_open+0x20/0x30 [<ffffffff816807c2>] system_call_fastpath+0x16/0x1b -> #0 (big_tty_mutex){+.+.+.}: [<ffffffff810bea8e>] __lock_acquire+0x16ee/0x1c60 [<ffffffff810bf70d>] lock_acquire+0x9d/0x1f0 [<ffffffff816750e4>] mutex_lock_nested+0x74/0x3a0 [<ffffffff81678127>] tty_lock+0x17/0x19 [<ffffffff813c184d>] tty_port_close_start+0x17d/0x210 [<ffffffffa055b32f>] acm_tty_close+0x4f/0xc0 [cdc_acm] [<ffffffff813b90a7>] tty_release+0x167/0x5c0 [<ffffffff811af073>] fput+0x103/0x290 [<ffffffff811aa939>] filp_close+0x69/0x90 [<ffffffff811aac20>] sys_close+0xc0/0x1a0 [<ffffffff816807c2>] system_call_fastpath+0x16/0x1b other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(open_mutex); lock(big_tty_mutex); lock(open_mutex); lock(big_tty_mutex); *** DEADLOCK *** 1 lock held by modem-manager/1122: #0: (open_mutex){+.+...}, at: [<ffffffffa055b321>] acm_tty_close+0x41/0xc0 [cdc_acm] stack backtrace: Pid: 1122, comm: modem-manager Not tainted 3.2.0-0.rc7.git0.1.fc17.x86_64 #1 Call Trace: [<ffffffff8166b192>] print_circular_bug+0x202/0x213 [<ffffffff810bea8e>] __lock_acquire+0x16ee/0x1c60 [<ffffffff81020d19>] ? sched_clock+0x9/0x10 [<ffffffff810abd4d>] ? sched_clock_cpu+0xbd/0x110 [<ffffffff810bf70d>] lock_acquire+0x9d/0x1f0 [<ffffffff81678127>] ? tty_lock+0x17/0x19 [<ffffffff81678127>] ? tty_lock+0x17/0x19 [<ffffffff816750e4>] mutex_lock_nested+0x74/0x3a0 [<ffffffff81678127>] ? tty_lock+0x17/0x19 [<ffffffff813beb2e>] ? tty_wait_until_sent+0x4e/0x120 [<ffffffff810c035d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81678127>] tty_lock+0x17/0x19 [<ffffffff813c184d>] tty_port_close_start+0x17d/0x210 [<ffffffffa055b32f>] acm_tty_close+0x4f/0xc0 [cdc_acm] [<ffffffff813b90a7>] tty_release+0x167/0x5c0 [<ffffffff811af073>] fput+0x103/0x290 [<ffffffff811aa939>] filp_close+0x69/0x90 [<ffffffff811aac20>] sys_close+0xc0/0x1a0 [<ffffffff816807c2>] system_call_fastpath+0x16/0x1b