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| author | Nicholas Piggin <npiggin@gmail.com> | 2017-06-21 15:58:29 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-06-23 13:25:38 +1000 |
| commit | 34f19ff1b5a0d11e46df479623d6936460105c9f (patch) | |
| tree | cb5697ee0cac4b2db8afbf9127be4f920eff0cba /scripts/const_structs.checkpatch | |
| parent | powerpc/powernv/npu-dma: Add explicit flush when sending an ATSD (diff) | |
| download | linux-34f19ff1b5a0d11e46df479623d6936460105c9f.tar.gz linux-34f19ff1b5a0d11e46df479623d6936460105c9f.zip | |
powerpc/64: Initialise thread_info for emergency stacks
Emergency stacks have their thread_info mostly uninitialised, which in
particular means garbage preempt_count values.
Emergency stack code runs with interrupts disabled entirely, and is
used very rarely, so this has been unnoticed so far. It was found by a
proposed new powerpc watchdog that takes a soft-NMI directly from the
masked_interrupt handler and using the emergency stack. That crashed
at BUG_ON(in_nmi()) in nmi_enter(). preempt_count()s were found to be
garbage.
To fix this, zero the entire THREAD_SIZE allocation, and initialize
the thread_info.
Cc: stable@vger.kernel.org
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move it all into setup_64.c, use a function not a macro. Fix
crashes on Cell by setting preempt_count to 0 not HARDIRQ_OFFSET]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'scripts/const_structs.checkpatch')
0 files changed, 0 insertions, 0 deletions