x86: mm/fault: Fix semaphore imbalance
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Invalid
|
Undecided
|
Luis Henriques | ||
Precise |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
The qrt kernel_security are hanging with "task hung" errors/warnings on the console with Precise. This seems to be due to an issue in the backport to the 3.2.67 stable kernel of commit:
commit 33692f27597fcab
Author: Linus Torvalds <email address hidden>
Date: Thu Jan 29 10:51:32 2015 -0800
vm: add VM_FAULT_SIGSEGV handling support
3.2.68 kernel fixes this issue with commit:
commit 6749fd110bf4416
Author: Ben Hutchings <email address hidden>
Date: Wed Feb 25 00:02:28 2015 +0000
x86: mm/fault: Fix semaphore imbalance
When backporting commit 33692f27597f ('vm: add VM_FAULT_SIGSEGV
handling support') I didn't notice that it depended on a recent change
to the locking context of mm_fault_error() (commit 7fb08eca4527,
'x86: mm: move mmap_sem unlock from mm_fault_error() to caller').
That isn't easily applicable to 3.2, so instead make sure we drop
mm->mmap_sem on the new branch of mm_fault_error().
The ubuntu-qrt-apparmor are also hanging, possibly for the same reason.
Including commit 6749fd110bf4 ("x86: mm/fault: Fix semaphore imbalance") in Precise seems to fix these issues.
CVE References
Changed in linux (Ubuntu Precise): | |
status: | New → Triaged |
Changed in linux (Ubuntu Precise): | |
status: | Triaged → Fix Committed |
Changed in linux (Ubuntu): | |
status: | Triaged → Invalid |
tags: |
added: verification-needed-done removed: verification-needed-precise |
tags: |
added: verification-done-precise removed: verification-needed-done |
This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification- needed- precise' to 'verification- done-precise' .
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
See https:/ /wiki.ubuntu. com/Testing/ EnableProposed for documentation how to enable and use -proposed. Thank you!