Commit ebf2d268 authored Jun 22, 2015 by Yann Droneaud Committed by Ingo Molnar Jul 06, 2015

perf/x86: Fix copy_from_user_nmi() return if range is not ok



Commit 0a196848 ("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 0a196848, the function should be
fixed to return the total number of bytes if range is
not correct.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435001923-30986-1-git-send-email-ydroneaud@opteya.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 57ffc5ca

arch/x86/lib/usercopy.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -20,7 +20,7 @@ copy_from_user_nmi(void to, const void __user from, unsigned long n)
	unsigned long ret;		unsigned long ret;

	if (__range_not_ok(from, n, TASK_SIZE))		if (__range_not_ok(from, n, TASK_SIZE))
	return 0;		return n;

	/*		/*
	* Even though this function is typically called from NMI/IRQ context		* Even though this function is typically called from NMI/IRQ context

Admin message