Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 2/3] irq: Execute softirq on its own stack on irq exit | Date | Thu, 5 Sep 2013 17:33:23 +0200 |
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When a softirq executes in irq_exit(), it can contribute to random complicated and large stack scenario involving task calls, hw interrupt calls, softirq handler calls and then other irqs, interrupting the softirq, that can dig further with an irq handler.
Softirqs executing on the inline hw interrupt stack may favour stack overflows in such circumstances, as it has been reported in powerpc where task -> irq -> softirq -> irq can end up forming a huge calltrace in the single kernel stack.
So if there are softirqs pending on hardirq exit, lets execute them on the softirq stack to minimize this.
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Andrew Morton <akpm@linux-foundation.org> --- kernel/softirq.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c index 39d27ff..657e047 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -326,7 +326,7 @@ void irq_enter(void) static inline void invoke_softirq(void) { if (!force_irqthreads) - __do_softirq(); + do_softirq_own_stack(); else wakeup_softirqd(); } -- 1.7.5.4
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