From: David S. Miller Date: Mon, 15 Oct 2012 00:59:40 +0000 (-0700) Subject: sparc64: Like x86 we should check current->mm during perf backtrace generation. X-Git-Tag: v3.2.33~93 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6471fbc6eb71dd615075f58576ad813697700873;p=karo-tx-linux.git sparc64: Like x86 we should check current->mm during perf backtrace generation. [ Upstream commit 08280e6c4c2e8049ac61d9e8e3536ec1df629c0d ] If the MM is not active, only report the top-level PC. Do not try to access the address space. Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 614da624330c..5331ae177472 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -1422,8 +1422,6 @@ static void perf_callchain_user_64(struct perf_callchain_entry *entry, { unsigned long ufp; - perf_callchain_store(entry, regs->tpc); - ufp = regs->u_regs[UREG_I6] + STACK_BIAS; do { struct sparc_stackf *usf, sf; @@ -1444,8 +1442,6 @@ static void perf_callchain_user_32(struct perf_callchain_entry *entry, { unsigned long ufp; - perf_callchain_store(entry, regs->tpc); - ufp = regs->u_regs[UREG_I6] & 0xffffffffUL; do { struct sparc_stackf32 *usf, sf; @@ -1464,6 +1460,11 @@ static void perf_callchain_user_32(struct perf_callchain_entry *entry, void perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { + perf_callchain_store(entry, regs->tpc); + + if (!current->mm) + return; + flushw_user(); if (test_thread_flag(TIF_32BIT)) perf_callchain_user_32(entry, regs);