Revision 529871bb3c0675d0b425e2070d5a739db097be98 authored by Juergen Gross on 28 July 2017, 14:53:55 UTC, committed by Juergen Gross on 11 August 2017, 14:45:56 UTC
When starting the xenwatch thread a theoretical deadlock situation is
possible:
xs_init() contains:
task = kthread_run(xenwatch_thread, NULL, "xenwatch");
if (IS_ERR(task))
return PTR_ERR(task);
xenwatch_pid = task->pid;
And xenwatch_thread() does:
mutex_lock(&xenwatch_mutex);
...
event->handle->callback();
...
mutex_unlock(&xenwatch_mutex);
The callback could call unregister_xenbus_watch() which does:
...
if (current->pid != xenwatch_pid)
mutex_lock(&xenwatch_mutex);
...
In case a watch is firing before xenwatch_pid could be set and the
callback of that watch unregisters a watch, then a self-deadlock would
occur.
Avoid this by setting xenwatch_pid in xenwatch_thread().
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
1 parent 4ca83dc
| File | Mode | Size |
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 31 bytes |
| .gitattributes | -rw-r--r-- | 30 bytes |
| .gitignore | -rw-r--r-- | 1.3 KB |
| .mailmap | -rw-r--r-- | 8.1 KB |
| COPYING | -rw-r--r-- | 18.3 KB |
| CREDITS | -rw-r--r-- | 96.2 KB |
| Kbuild | -rw-r--r-- | 2.2 KB |
| Kconfig | -rw-r--r-- | 252 bytes |
| MAINTAINERS | -rw-r--r-- | 411.0 KB |
| Makefile | -rw-r--r-- | 58.8 KB |
| README | -rw-r--r-- | 722 bytes |
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