The patch titled
Subject: fs/exec.c: work around icc miscompilation
has been added to the -mm tree. Its filename is
fs-execc-work-around-icc-miscompilation.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Xi Wang <xi.wang@xxxxxxxxx>
Subject: fs/exec.c: work around icc miscompilation
The tricky problem is this check:
if (i++ >= max)
icc (mis)optimizes this check as:
if (++i > max)
The check now becomes a no-op since max is MAX_ARG_STRINGS (0x7FFFFFFF).
This is "allowed" by the C standard, assuming i++ never overflows,
because signed integer overflow is undefined behavior. This optimization
effectively reverts the previous commit 362e6663ef ("exec.c, compat.c:
fix count(), compat_count() bounds checking") that tries to fix the check.
This patch simply moves ++ after the check.
Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN fs/exec.c~fs-execc-work-around-icc-miscompilation fs/exec.c
--- a/fs/exec.c~fs-execc-work-around-icc-miscompilation
+++ a/fs/exec.c
@@ -434,8 +434,9 @@ static int count(struct user_arg_ptr arg
if (IS_ERR(p))
return -EFAULT;
- if (i++ >= max)
+ if (i >= max)
return -E2BIG;
+ ++i;
if (fatal_signal_pending(current))
return -ERESTARTNOHAND;
_
Patches currently in -mm which might be from xi.wang@xxxxxxxxx are
origin.patch
linux-next.patch
fs-execc-work-around-icc-miscompilation.patch
drivers-usb-gadget-amd5536udcc-avoid-calling-dma_pool_create-with-null-dev.patch
mm-dmapoolc-fix-null-dev-in-dma_pool_create.patch
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