From 0562337b7aaee1c50fa840e220eba4f7478a9e82 Mon Sep 17 00:00:00 2001 From: Dimitri Staessens Date: Sun, 5 Jul 2026 18:07:42 +0200 Subject: lib: Clean up on cancelled blocking read Cancelling a thread that was blocked in ssm_rbuff_read_b/write_b didn't clean up the n_users reference. If it was in flow_rx_one it didn't unlock the process lock. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders --- src/lib/dev.c | 5 +++++ src/lib/ssm/rbuff.c | 19 +++++++++++++++---- 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/src/lib/dev.c b/src/lib/dev.c index d0997273..c4c874cc 100644 --- a/src/lib/dev.c +++ b/src/lib/dev.c @@ -615,7 +615,12 @@ static int flow_rx_one(struct flow * flow, continue; } + pthread_cleanup_push(__cleanup_rwlock_unlock, &proc.lock); + idx = ssm_rbuff_read_b(rx_rb, &wait_abs); + + pthread_cleanup_pop(false); + if (idx == -ETIMEDOUT) { pthread_rwlock_unlock(&proc.lock); if (deadline_passed(abs)) diff --git a/src/lib/ssm/rbuff.c b/src/lib/ssm/rbuff.c index 0121af89..7886b5c2 100644 --- a/src/lib/ssm/rbuff.c +++ b/src/lib/ssm/rbuff.c @@ -242,6 +242,15 @@ void ssm_rbuff_close(struct ssm_rbuff * rb) rbuff_destroy(rb); } +/* Cancel cleanup for a blocked reader: unlock mtx AND drop the n_users ref. */ +static void __cleanup_rbuff_reader(void * o) +{ + struct ssm_rbuff * rb = (struct ssm_rbuff *) o; + + pthread_mutex_unlock(rb->mtx); + __atomic_fetch_sub(&rb->n_users, 1, __ATOMIC_SEQ_CST); +} + int ssm_rbuff_write(struct ssm_rbuff * rb, size_t off) { @@ -318,7 +327,7 @@ int ssm_rbuff_write_b(struct ssm_rbuff * rb, robust_mutex_lock(rb->mtx); - pthread_cleanup_push(__cleanup_mutex_unlock, rb->mtx); + pthread_cleanup_push(__cleanup_rbuff_reader, rb); while (IS_FULL(rb) && ret != -ETIMEDOUT) { flags = __atomic_load_n(rb->flags, __ATOMIC_SEQ_CST); @@ -417,7 +426,7 @@ ssize_t ssm_rbuff_read_b(struct ssm_rbuff * rb, robust_mutex_lock(rb->mtx); - pthread_cleanup_push(__cleanup_mutex_unlock, rb->mtx); + pthread_cleanup_push(__cleanup_rbuff_reader, rb); while (IS_EMPTY(rb) && idx != -ETIMEDOUT && @@ -483,12 +492,14 @@ void ssm_rbuff_fini(struct ssm_rbuff * rb) robust_mutex_lock(rb->mtx); - pthread_cleanup_push(__cleanup_mutex_unlock, rb->mtx); + pthread_cleanup_push(__cleanup_rbuff_reader, rb); while (!IS_EMPTY(rb)) robust_wait(rb->del, rb->mtx, NULL); - pthread_cleanup_pop(true); + pthread_cleanup_pop(false); + + pthread_mutex_unlock(rb->mtx); __atomic_fetch_sub(&rb->n_users, 1, __ATOMIC_SEQ_CST); } -- cgit v1.2.3