* [PATCH AUTOSEL 6.1 4/9] io_uring/sqpoll: work around a potential audit memory leak
[not found] <[email protected]>
@ 2024-05-26 9:43 ` Sasha Levin
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From: Sasha Levin @ 2024-05-26 9:43 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Jens Axboe, Sasha Levin, io-uring
From: Jens Axboe <[email protected]>
[ 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 <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
io_uring/sqpoll.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 7b6facf529b8d..11610a70573ab 100644
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -235,6 +235,14 @@ static int io_sq_thread(void *data)
set_cpus_allowed_ptr(current, cpu_online_mask);
current->flags |= PF_NO_SETAFFINITY;
+ /*
+ * 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;
--
2.43.0
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