3.11.10.2 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Mateusz Guzik <[email protected]> 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 <[email protected]> Reported-by: Eryu Guan <[email protected]> Cc: Jeff Moyer <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: [email protected] Cc: [email protected] Acked-by: Benjamin LaHaise <[email protected]> Signed-off-by: Luis Henriques <[email protected]> --- fs/aio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 9b5ca11..975a5d5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -425,10 +425,12 @@ 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 @@ -496,7 +498,7 @@ void exit_aio(struct mm_struct *mm) */ ctx->mmap_size = 0; - kill_ioctx(ctx); + kill_ioctx(mm, ctx); } } @@ -854,7 +856,7 @@ 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); } @@ -872,7 +874,7 @@ 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; } -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
