diff options
| author | Dima Zavin <dima@android.com> | 2011-10-09 02:20:50 +0100 |
|---|---|---|
| committer | Andy Green <andy.green@linaro.org> | 2011-10-09 02:20:50 +0100 |
| commit | 308b3c8e8f9868b6e2282aab8454616caace7879 (patch) | |
| tree | c0bee5dd7bd71062bf6cc19b2568d2eac281a178 /arch/arm/include | |
| parent | 843e35f36e72ad9338a499f1bf08265a53f8d5ba (diff) | |
Do not call flush_cache_user_range with mmap_sem held
We can't be holding the mmap_sem while calling flush_cache_user_range
because the flush can fault. If we fault on a user address, the
page fault handler will try to take mmap_sem again. Since both places
acquire the read lock, most of the time it succeeds. However, if another
thread tries to acquire the write lock on the mmap_sem (e.g. mmap) in
between the call to flush_cache_user_range and the fault, the down_read
in do_page_fault will deadlock.
Also, since we really can't be holding the mmap_sem while calling
flush_cache_user_range AND vma is actually unused by the flush itself,
get rid of vma as an argument.
Change-Id: If55409bde41ad1060fa4fe7cbd4ac530d4d9a106
Signed-off-by: Dima Zavin <dima@android.com>
Diffstat (limited to 'arch/arm/include')
| -rw-r--r-- | arch/arm/include/asm/cacheflush.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index d5d8d5c7268..1252a2675ca 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -249,7 +249,7 @@ extern void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr * Harvard caches are synchronised for the user space address range. * This is used for the ARM private sys_cacheflush system call. */ -#define flush_cache_user_range(vma,start,end) \ +#define flush_cache_user_range(start,end) \ __cpuc_coherent_user_range((start) & PAGE_MASK, PAGE_ALIGN(end)) /* |