x86/ldt: use vfree_atomic() to free ldt entries
authorAndrey Ryabinin <aryabinin@virtuozzo.com>
Tue, 13 Dec 2016 00:44:17 +0000 (16:44 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 13 Dec 2016 02:55:08 +0000 (18:55 -0800)
vfree() is going to use sleeping lock.  free_ldt_struct() may be called
with disabled preemption, therefore we must use vfree_atomic() here.

E.g. call trace:
vfree()
free_ldt_struct()
destroy_context_ldt()
__mmdrop()
finish_task_switch()
schedule_tail()
ret_from_fork()

Link: http://lkml.kernel.org/r/1479474236-4139-7-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/x86/kernel/ldt.c

index 6707039b9032d98ebdb21b37769d4e400fa80cd0..4d12cdf2b4537d039e7da35566b235acfe04ef9e 100644 (file)
@@ -93,7 +93,7 @@ static void free_ldt_struct(struct ldt_struct *ldt)
 
        paravirt_free_ldt(ldt->entries, ldt->size);
        if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
-               vfree(ldt->entries);
+               vfree_atomic(ldt->entries);
        else
                free_page((unsigned long)ldt->entries);
        kfree(ldt);