6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Olivier Langlois [ Upstream commit 2f3cc8e441c9f657ff036c56baaab7dddbd0b350 ] io_napi_entry timeout value can be updated while accessed from the poll functions. Its concurrent accesses are wrapped with READ_ONCE()/WRITE_ONCE() macros to avoid incorrect compiler optimizations. Signed-off-by: Olivier Langlois Link: https://lore.kernel.org/r/3de3087563cf98f75266fd9f85fdba063a8720db.1728828877.git.olivier@trillion01.com Signed-off-by: Jens Axboe Stable-dep-of: df8599ee18c0 ("io_uring/napi: cap busy_poll_to 10 msec") Signed-off-by: Sasha Levin --- io_uring/napi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/io_uring/napi.c b/io_uring/napi.c index fa959fd320429..921de9de8d753 100644 --- a/io_uring/napi.c +++ b/io_uring/napi.c @@ -60,7 +60,7 @@ void __io_napi_add(struct io_ring_ctx *ctx, struct socket *sock) rcu_read_lock(); e = io_napi_hash_find(hash_list, napi_id); if (e) { - e->timeout = jiffies + NAPI_TIMEOUT; + WRITE_ONCE(e->timeout, jiffies + NAPI_TIMEOUT); rcu_read_unlock(); return; } @@ -155,7 +155,7 @@ static bool __io_napi_do_busy_loop(struct io_ring_ctx *ctx, napi_busy_loop_rcu(e->napi_id, loop_end, loop_end_arg, ctx->napi_prefer_busy_poll, BUSY_POLL_BUDGET); - if (time_after(jiffies, e->timeout)) + if (time_after(jiffies, READ_ONCE(e->timeout))) is_stale = true; } -- 2.53.0