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authorAl Viro <viro@zeniv.linux.org.uk>2015-04-07 00:57:44 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-04-07 00:57:44 +0300
commitdeeb8525f9bcea60f5e86521880c1161de7a5829 (patch)
tree49786da6f302e84cf94e2af32e06b159432d26bc /fs/aio.c
parentb2edffdd912b4205899a8efa0974dfbbc3216109 (diff)
downloadlinux-deeb8525f9bcea60f5e86521880c1161de7a5829.tar.xz
ioctx_alloc(): fix vma (and file) leak on failure
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 <jmario@redhat.com>): 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 <jmario@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 58c33dcfb6ca..a793f7023755 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -731,6 +731,9 @@ 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);