A flaw was found in the linux kernel which could cause a kernel panic when restoring machine specific registers on the power pc platform. Incorrect transactional memory state registers could inadvertently change the call path on return from userspace and cause the kernel to enter an unknown state and panic defensively. The message is usually as follows: kernel BUG at arch/powerpc/kernel/tm.S:177 Call Trace: [c0000001cb41ba60] [c000000000015b40] .tm_reclaim_current+0xa0/0x120 [c0000001cb41bb00] [c000000000018188] .get_tm_stackpointer+0x48/0x80 [c0000001cb41bb80] [c000000000025634] .handle_rt_signal64+0x64/0x7c0 [c0000001cb41bc70] [c000000000017db8] .do_signal+0x168/0x320 [c0000001cb41bdb0] [c0000000000180cc] .do_notify_resume+0x8c/0x100 In this situation, the transactional memory state has not been initiated correctly for the handler to work, and the BUG() is triggered. References (Fixes): https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=d2b9d2a5ad5ef04ff978c9923d19730cb05efd55 https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=7f821fc9c77a9b01fe7b1d6e72717b33d8d64142 Oss-sec post: http://seclists.org/oss-sec/2016/q2/64
Acknowledgements: Name: Miroslav Vadkerti (Red Hat Engineering)
Statement: This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 5 and 6, This issue affects the Linux kernels as shipped with Red Hat Enterprise Linux 7 and MRG-2 realtime kernels. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/ .
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1326649]
(In reply to Wade Mealing from comment #0) > In this situation, the transactional memory state has not been initiated > correctly for the handler to work, and the BUG() is triggered. > > References: > https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/commit/ > ?h=fixes&id=d2b9d2a5ad5ef04ff978c9923d19730cb05efd55 > > https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/commit/ > ?h=fixes&id=7f821fc9c77a9b01fe7b1d6e72717b33d8d64142 Are these commits fixes for this issue, or are they the commits that introduced this issue?
I believe those are the two that fixes the issue, sorry should have made that clearer.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2016:2574 https://rhn.redhat.com/errata/RHSA-2016-2574.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2016:2584 https://rhn.redhat.com/errata/RHSA-2016-2584.html