From 3b614ad6a1915f700fafc65495bfbcfd6cebf056 Mon Sep 17 00:00:00 2001 From: Yann Droneaud Date: Mon, 22 Jun 2015 21:38:43 +0200 Subject: [PATCH] perf/x86: Fix copy_from_user_nmi() return if range is not ok Commit dcc75f3d190d ("perf: Fix arch_perf_out_copy_user default"), changes copy_from_user_nmi() to return the number of remaining bytes so that it behave like copy_from_user(). Unfortunately, when the range is outside of the process memory, the return value is still the number of byte copied, eg. 0, instead of the remaining bytes. As all users of copy_from_user_nmi() were modified as part of commit dcc75f3d190d, the function should be fixed to return the total number of bytes if range is not correct. Signed-off-by: Yann Droneaud Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1435001923-30986-1-git-send-email-ydroneaud@opteya.com Signed-off-by: Ingo Molnar --- arch/x86/lib/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c index ddf9ecb53cc3e..e342586db6e4b 100644 --- a/arch/x86/lib/usercopy.c +++ b/arch/x86/lib/usercopy.c @@ -20,7 +20,7 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) unsigned long ret; if (__range_not_ok(from, n, TASK_SIZE)) - return 0; + return n; /* * Even though this function is typically called from NMI/IRQ context -- 2.39.5