diff options
| author | Andi Kleen <andi@firstfloor.org> | 2009-12-08 13:19:42 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2009-12-08 15:03:26 +0100 |
| commit | cc24da0742870f152ddf1002aa39dfcd83f7cf9c (patch) | |
| tree | 2cf6a4209372892aa24ff30cf7a41ab5574ac62e | |
| parent | 05d5f5080a2e3fbbc0f762875b66721588f5e251 (diff) | |
| download | lwn-cc24da0742870f152ddf1002aa39dfcd83f7cf9c.tar.gz lwn-cc24da0742870f152ddf1002aa39dfcd83f7cf9c.zip | |
futex: Take mmap_sem for get_user_pages in fault_in_user_writeablev2.6.31-rt-head
get_user_pages() must be called with mmap_sem held.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: stable@kernel.org
Cc: Andrew Morton <akpm@linuxfoundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20091208121942.GA21298@basil.fritz.box>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | kernel/futex.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index b2400110b6c8..da333ceed739 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -304,8 +304,14 @@ void put_futex_key(int fshared, union futex_key *key) */ static int fault_in_user_writeable(u32 __user *uaddr) { - int ret = get_user_pages(current, current->mm, (unsigned long)uaddr, - 1, 1, 0, NULL, NULL); + struct mm_struct *mm = current->mm; + int ret; + + down_read(&mm->mmap_sem); + ret = get_user_pages(current, mm, (unsigned long)uaddr, + 1, 1, 0, NULL, NULL); + up_read(&mm->mmap_sem); + return ret < 0 ? ret : 0; } |