From mboxrd@z Thu Jan 1 00:00:00 1970 From: jean.pihet@linaro.org (Jean Pihet) Date: Fri, 27 Jun 2014 16:57:45 +0200 Subject: [PATCH 1/3] ARM: perf: Check that current->mm is alive before getting user callchain In-Reply-To: <1403881067-22690-1-git-send-email-jean.pihet@linaro.org> References: <1403881067-22690-1-git-send-email-jean.pihet@linaro.org> Message-ID: <1403881067-22690-2-git-send-email-jean.pihet@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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' Signed-off-by: Jean Pihet Cc: Will Deacon --- arch/arm/kernel/perf_event.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 4238bcb..6493c4c 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -590,6 +590,10 @@ 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) && -- 1.8.1.2