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.
Change-Id: Ibf70e96343d35587571968bbc39062e28b7d3c0a
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
1 file changed