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: v3.6.4~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f386dbc80c65fe40a5a76806358a5e565086e23c;p=thirdparty%2Fkernel%2Fstable.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: Greg Kroah-Hartman --- diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 5713957dcb8a3..b0cce262f8381 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -1426,8 +1426,6 @@ 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; @@ -1448,8 +1446,6 @@ 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; @@ -1468,6 +1464,11 @@ 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);