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author | Vikram Mulukutla <markivx@codeaurora.org> | 2012-07-30 14:39:58 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-30 17:25:13 -0700 |
commit | 190320c3b6640d4104650f55ff69611e050ea06b (patch) | |
tree | 94d43c11e025e4b4efc577a2cf88a29250d4f510 /kernel/power | |
parent | 6c55845e71ba7a862395f504a240a5b62632e0d6 (diff) | |
download | linux-190320c3b6640d4104650f55ff69611e050ea06b.tar.gz linux-190320c3b6640d4104650f55ff69611e050ea06b.tar.bz2 linux-190320c3b6640d4104650f55ff69611e050ea06b.zip |
panic: fix a possible deadlock in panic()
panic_lock is meant to ensure that panic processing takes place only on
one cpu; if any of the other cpus encounter a panic, they will spin
waiting to be shut down.
However, this causes a regression in this scenario:
1. Cpu 0 encounters a panic and acquires the panic_lock
and proceeds with the panic processing.
2. There is an interrupt on cpu 0 that also encounters
an error condition and invokes panic.
3. This second invocation fails to acquire the panic_lock
and enters the infinite while loop in panic_smp_self_stop.
Thus all panic processing is stopped, and the cpu is stuck for eternity
in the while(1) inside panic_smp_self_stop.
To address this, disable local interrupts with local_irq_disable before
acquiring the panic_lock. This will prevent interrupt handlers from
executing during the panic processing, thus avoiding this particular
problem.
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/power')
0 files changed, 0 insertions, 0 deletions