diff options
| -rw-r--r-- | fs/io_uring.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 5dcc77b42f0d..556e4a2ead07 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8414,11 +8414,19 @@ static int io_uring_show_cred(int id, void *p, void *data) static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) { + bool has_lock; int i; - mutex_lock(&ctx->uring_lock); + /* + * Avoid ABBA deadlock between the seq lock and the io_uring mutex, + * since fdinfo case grabs it in the opposite direction of normal use + * cases. If we fail to get the lock, we just don't iterate any + * structures that could be going away outside the io_uring mutex. + */ + has_lock = mutex_trylock(&ctx->uring_lock); + seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); - for (i = 0; i < ctx->nr_user_files; i++) { + for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct fixed_file_table *table; struct file *f; @@ -8430,13 +8438,13 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) seq_printf(m, "%5u: <none>\n", i); } seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); - for (i = 0; i < ctx->nr_user_bufs; i++) { + for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *buf = &ctx->user_bufs[i]; seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, (unsigned int) buf->len); } - if (!idr_is_empty(&ctx->personality_idr)) { + if (has_lock && !idr_is_empty(&ctx->personality_idr)) { seq_printf(m, "Personalities:\n"); idr_for_each(&ctx->personality_idr, io_uring_show_cred, m); } @@ -8451,7 +8459,8 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) req->task->task_works != NULL); } spin_unlock_irq(&ctx->completion_lock); - mutex_unlock(&ctx->uring_lock); + if (has_lock) + mutex_unlock(&ctx->uring_lock); } static void io_uring_show_fdinfo(struct seq_file *m, struct file *f) |