From fe4a6fceff3949a6389c582ccedc393670355469 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 6 Apr 2015 17:57:44 -0400 Subject: [PATCH] ioctx_alloc(): fix vma (and file) leak on failure [ Upstream commit deeb8525f9bcea60f5e86521880c1161de7a5829 ] If we fail past the aio_setup_ring(), we need to destroy the mapping. We don't need to care about anybody having found ctx, or added requests to it, since the last failure exit is exactly the failure to make ctx visible to lookups. Reproducer (based on one by Joe Mario ): void count(char *p) { char s[80]; printf("%s: ", p); fflush(stdout); sprintf(s, "/bin/cat /proc/%d/maps|/bin/fgrep -c '/[aio] (deleted)'", getpid()); system(s); } int main() { io_context_t *ctx; int created, limit, i, destroyed; FILE *f; count("before"); if ((f = fopen("/proc/sys/fs/aio-max-nr", "r")) == NULL) perror("opening aio-max-nr"); else if (fscanf(f, "%d", &limit) != 1) fprintf(stderr, "can't parse aio-max-nr\n"); else if ((ctx = calloc(limit, sizeof(io_context_t))) == NULL) perror("allocating aio_context_t array"); else { for (i = 0, created = 0; i < limit; i++) { if (io_setup(1000, ctx + created) == 0) created++; } for (i = 0, destroyed = 0; i < created; i++) if (io_destroy(ctx[i]) == 0) destroyed++; printf("created %d, failed %d, destroyed %d\n", created, limit - created, destroyed); count("after"); } } Found-by: Joe Mario Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/aio.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/aio.c b/fs/aio.c index 14b9315..58caa7e 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -715,6 +715,9 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) err_cleanup: aio_nr_sub(ctx->max_reqs); err_ctx: + atomic_set(&ctx->dead, 1); + if (ctx->mmap_size) + vm_munmap(ctx->mmap_base, ctx->mmap_size); aio_free_ring(ctx); err: mutex_unlock(&ctx->ring_lock); -- 2.7.4