From a40e90d9304629002fb17200f7779823a81191d3 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 21 Mar 2024 07:38:38 -0600 Subject: [PATCH] io_uring/sqpoll: work around a potential audit memory leak [ Upstream commit c4ce0ab27646f4206a9eb502d6fe45cb080e1cae ] kmemleak complains that there's a memory leak related to connect handling: unreferenced object 0xffff0001093bdf00 (size 128): comm "iou-sqp-455", pid 457, jiffies 4294894164 hex dump (first 32 bytes): 02 00 fa ea 7f 00 00 01 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 2e481b1a): [<00000000c0a26af4>] kmemleak_alloc+0x30/0x38 [<000000009c30bb45>] kmalloc_trace+0x228/0x358 [<000000009da9d39f>] __audit_sockaddr+0xd0/0x138 [<0000000089a93e34>] move_addr_to_kernel+0x1a0/0x1f8 [<000000000b4e80e6>] io_connect_prep+0x1ec/0x2d4 [<00000000abfbcd99>] io_submit_sqes+0x588/0x1e48 [<00000000e7c25e07>] io_sq_thread+0x8a4/0x10e4 [<00000000d999b491>] ret_from_fork+0x10/0x20 which can can happen if: 1) The command type does something on the prep side that triggers an audit call. 2) The thread hasn't done any operations before this that triggered an audit call inside ->issue(), where we have audit_uring_entry() and audit_uring_exit(). Work around this by issuing a blanket NOP operation before the SQPOLL does anything. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- io_uring/sqpoll.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 158ab09c605b..b3722e5275e7 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -293,6 +293,14 @@ static int io_sq_thread(void *data) sqd->sq_cpu = raw_smp_processor_id(); } + /* + * Force audit context to get setup, in case we do prep side async + * operations that would trigger an audit call before any issue side + * audit has been done. + */ + audit_uring_entry(IORING_OP_NOP); + audit_uring_exit(true, 0); + mutex_lock(&sqd->lock); while (1) { bool cap_entries, sqt_spin = false;