Eric Lee / linux-smarc-t335x-v3.2

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Commit 722d0172377a5697919b9f7e5beb95165b1dec4e

Authored by Andi Kleen
Committed by Thomas Gleixner
1 parent f5754bfd10
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

futex: Take mmap_sem for get_user_pages in fault_in_user_writeable 

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>

Showing 1 changed file with 8 additions and 2 deletions Side-by-side Diff

... ... @@ -304,8 +304,14 @@
304 304 */
305 305 static int fault_in_user_writeable(u32 __user *uaddr)
306 306 {
307   - int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
308   - 1, 1, 0, NULL, NULL);
  307 + struct mm_struct *mm = current->mm;
  308 + int ret;
  309 +
  310 + down_read(&mm->mmap_sem);
  311 + ret = get_user_pages(current, mm, (unsigned long)uaddr,
  312 + 1, 1, 0, NULL, NULL);
  313 + up_read(&mm->mmap_sem);
  314 +
309 315 return ret < 0 ? ret : 0;
310 316 }
311 317