The patch titled
Subject: mm/fremap.c: fix possible oops on error path
has been removed from the -mm tree. Its filename was
mm-fremapc-fix-possible-oops-on-error-path.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michel Lespinasse <walken@xxxxxxxxxx>
Subject: mm/fremap.c: fix possible oops on error path
The vm_flags introduced in 6d7825b10dbe ("mm/fremap.c: fix oops on error
path") is supposed to avoid a compiler warning about unitialized vm_flags
without changing the generated code.
However I am concerned that this is going to be very brittle, and fail
with some compiler versions. The failure could be either of:
- compiler could actually load vma->vm_flags before checking for the
!vma condition, thus reintroducing the oops
- compiler could optimize out the !vma check, since the pointer just got
dereferenced shortly before (so the compiler knows it can't be NULL!)
I propose reversing this part of the change and initializing vm_flags to 0
just to avoid the bogus uninitialized use warning.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Tommi Rantala <tt.rantala@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/fremap.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN mm/fremap.c~mm-fremapc-fix-possible-oops-on-error-path mm/fremap.c
--- a/mm/fremap.c~mm-fremapc-fix-possible-oops-on-error-path
+++ a/mm/fremap.c
@@ -129,7 +129,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsign
struct vm_area_struct *vma;
int err = -EINVAL;
int has_write_lock = 0;
- vm_flags_t vm_flags;
+ vm_flags_t vm_flags = 0;
if (prot)
return err;
@@ -163,8 +163,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsign
* and that the remapped range is valid and fully within
* the single existing vma.
*/
- vm_flags = vma->vm_flags;
- if (!vma || !(vm_flags & VM_SHARED))
+ if (!vma || !(vma->vm_flags & VM_SHARED))
goto out;
if (!vma->vm_ops || !vma->vm_ops->remap_pages)
_
Patches currently in -mm which might be from walken@xxxxxxxxxx are
linux-next.patch
mm-remove-free_area_cache-use-in-powerpc-architecture.patch
mm-use-vm_unmapped_area-on-powerpc-architecture.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
rmap-recompute-pgoff-for-unmapping-huge-page.patch
mm-introduce-free_highmem_page-helper-to-free-highmem-pages-into-buddy-system.patch
mm-remove-free_area_cache.patch
mutex-subsystem-synchro-test-module.patch
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