From 0b2c8f8b6b0c7530e2866c95862546d0da2057b0 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 4 Jan 2019 10:23:10 -0800
Subject: [PATCH] i915: fix missing user_access_end() in page fault exception
case
When commit fddcd00a49e9 ("drm/i915: Force the slow path after a
user-write error") unified the error handling for various user access
problems, it didn't do the user_access_end() that is needed for the
unsafe_put_user() case.
It's not a huge deal: a missed user_access_end() will only mean that
SMAP protection isn't active afterwards, and for the error case we'll be
returning to user mode soon enough anyway. But it's wrong, and adding
the proper user_access_end() is trivial enough (and doing it for the
other error cases where it isn't needed doesn't hurt).
I noticed it while doing the same prep-work for changing
user_access_begin() that precipitated the access_ok() changes in commit
96d4f267e40f ("Remove 'type' argument from access_ok() function").
Fixes: fddcd00a49e9 ("drm/i915: Force the slow path after a user-write error")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: stable@kernel.org # v4.20
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index fee66ccebed6..55d8f9b8777f 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1605,6 +1605,7 @@ static int eb_copy_relocations(const struct i915_execbuffer *eb)
(char __user *)urelocs + copied,
len)) {
end_user:
+ user_access_end();
kvfree(relocs);
err = -EFAULT;
goto err;
--
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