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authorTang Chen <tangchen@cn.fujitsu.com>2013-02-22 16:33:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:13 -0800
commitaa00d89c2780d72d082a015e8cbb751e65fb30ee (patch)
treea326cbf62ab21d76af7c82c0038a985db77e69b1 /kernel/srcu.c
parente13fe8695c57fed678877a9f3f8e99fc637ff4fb (diff)
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sched: do not use cpu_to_node() to find an offlined cpu's node.
If a cpu is offline, its nid will be set to -1, and cpu_to_node(cpu) will return -1. As a result, cpumask_of_node(nid) will return NULL. In this case, find_next_bit() in for_each_cpu will get a NULL pointer and cause panic. Here is a call trace: Call Trace: <IRQ> select_fallback_rq+0x71/0x190 try_to_wake_up+0x2cb/0x2f0 wake_up_process+0x15/0x20 hrtimer_wakeup+0x22/0x30 __run_hrtimer+0x83/0x320 hrtimer_interrupt+0x106/0x280 smp_apic_timer_interrupt+0x69/0x99 apic_timer_interrupt+0x6f/0x80 There is a hrtimer process sleeping, whose cpu has already been offlined. When it is waken up, it tries to find another cpu to run, and get a -1 nid. As a result, cpumask_of_node(-1) returns NULL, and causes ernel panic. This patch fixes this problem by judging if the nid is -1. If nid is not -1, a cpu on the same node will be picked. Else, a online cpu on another node will be picked. Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Jiang Liu <liuj97@gmail.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/srcu.c')
0 files changed, 0 insertions, 0 deletions
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