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authorMateusz Guzik <mguzik@redhat.com>2013-12-05 11:09:02 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-08 07:29:27 -0800
commitf8715e7d2a096cedd1c5ef4768deae7126659dcf (patch)
treea013b91b5bd6f58d7adeea9b96bf4ce6b3ef7645 /fs/aio.c
parent604ae797e7cd1eca7897eac555961a5a25a9bde5 (diff)
downloadlinux-linaro-stable-f8715e7d2a096cedd1c5ef4768deae7126659dcf.tar.gz
aio: restore locking of ioctx list on removal
Commit 36f5588905c10a8c4568a210d601fe8c3c27e0f0 "aio: refcounting cleanup" resulted in ioctx_lock not being held during ctx removal, leaving the list susceptible to corruptions. In mainline kernel the issue went away as a side effect of db446a08c23d5475e6b08c87acca79ebb20f283c "aio: convert the ioctx list to table lookup v3". Fix the problem by restoring appropriate locking. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Reported-by: Eryu Guan <eguan@redhat.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Kent Overstreet <kmo@daterainc.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 2bbcacf74d0c..ebd06fd0de89 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -423,10 +423,12 @@ static void kill_ioctx_rcu(struct rcu_head *head)
* when the processes owning a context have all exited to encourage
* the rapid destruction of the kioctx.
*/
-static void kill_ioctx(struct kioctx *ctx)
+static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx)
{
if (!atomic_xchg(&ctx->dead, 1)) {
+ spin_lock(&mm->ioctx_lock);
hlist_del_rcu(&ctx->list);
+ spin_unlock(&mm->ioctx_lock);
/*
* It'd be more correct to do this in free_ioctx(), after all
@@ -494,7 +496,7 @@ void exit_aio(struct mm_struct *mm)
*/
ctx->mmap_size = 0;
- kill_ioctx(ctx);
+ kill_ioctx(mm, ctx);
}
}
@@ -852,7 +854,7 @@ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
if (!IS_ERR(ioctx)) {
ret = put_user(ioctx->user_id, ctxp);
if (ret)
- kill_ioctx(ioctx);
+ kill_ioctx(current->mm, ioctx);
put_ioctx(ioctx);
}
@@ -870,7 +872,7 @@ SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
{
struct kioctx *ioctx = lookup_ioctx(ctx);
if (likely(NULL != ioctx)) {
- kill_ioctx(ioctx);
+ kill_ioctx(current->mm, ioctx);
put_ioctx(ioctx);
return 0;
}