Commit-ID: ababae44108b0e94b58eef6cb5bd830bd040a47f Gitweb: http://git.kernel.org/tip/ababae44108b0e94b58eef6cb5bd830bd040a47f Author: Werner Pawlitschko <werner.pawlitschko@xxxxxxxx> AuthorDate: Tue, 27 Oct 2015 09:08:04 +0900 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Tue, 27 Oct 2015 09:18:34 +0900 x86/ioapic: Prevent NULL pointer dereference in setup_ioapic_dest() Commit 4857c91f0d19 changed the way how irq affinity is setup in setup_ioapic_dest() from using the core helper function to unconditionally calling the irq_set_affinity() callback of the underlying irq chip. That results in a NULL pointer dereference for the rare case where the underlying irq chip is lapic_chip which has no irq_set_affinity() callback. lapic_chip is occasionally used for the timer interrupt (irq 0). The fix is simple: Check the availability of the callback instead of calling it unconditionally. Fixes: 4857c91f0d19 "x86/ioapic: Force affinity setting in setup_ioapic_dest()" Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- arch/x86/kernel/apic/io_apic.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index bb6bfc0..4f28215 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2547,7 +2547,9 @@ void __init setup_ioapic_dest(void) mask = apic->target_cpus(); chip = irq_data_get_irq_chip(idata); - chip->irq_set_affinity(idata, mask, false); + /* Might be lapic_chip for irq 0 */ + if (chip->irq_set_affinity) + chip->irq_set_affinity(idata, mask, false); } } #endif -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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