From: Jean Pihet Date: Mon, 7 Jul 2014 13:45:08 +0000 (+0100) Subject: ARM: perf: Check that current->mm is alive before getting user callchain X-Git-Tag: sz_173~71 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1768736891543baf955e67d6565b7330f71e8984;p=pandora-kernel.git ARM: perf: Check that current->mm is alive before getting user callchain An event may occur when an mm is already released. As per commit 20afc60f892d285fde179ead4b24e6a7938c2f1b 'x86, perf: Check that current->mm is alive before getting user callchain' Acked-by: Will Deacon Signed-off-by: Jean Pihet Signed-off-by: Will Deacon --- diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 4a2db48c148e..c024d37ab7c7 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -804,6 +804,10 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) perf_callchain_store(entry, regs->ARM_pc); + + if (!current->mm) + return; + tail = (struct frame_tail __user *)regs->ARM_fp - 1; while ((entry->nr < PERF_MAX_STACK_DEPTH) &&