Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 37/43] ioctx_alloc(): fix vma (and file) leak on failure | Date | Fri, 17 Apr 2015 15:29:11 +0200 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro <viro@zeniv.linux.org.uk>
commit deeb8525f9bcea60f5e86521880c1161de7a5829 upstream.
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> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/aio.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/aio.c +++ b/fs/aio.c @@ -719,6 +719,9 @@ static struct kioctx *ioctx_alloc(unsign 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);
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