Messages in this thread Patch in this message | | | From | Mateusz Guzik <> | Subject | [PATCH 3.10] aio: restore locking of ioctx list on removal | Date | Thu, 5 Dec 2013 11:09:02 +0100 |
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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> Cc: linux-aio@kvack.org Cc: linux-kernel@vger.kernel.org
--- fs/aio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c index 2bbcacf..ebd06fd 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; } -- 1.8.3.1
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