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| author | Jan Beulich <jbeulich@suse.com> | 2021-02-15 10:56:44 +0300 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2021-02-15 10:56:44 +0300 |
| commit | 871997bc9e423f05c7da7c9178e62dde5df2a7f8 (patch) | |
| tree | 31bdf5ee41af83e487cd234fa7b947e5c9165a8b /drivers/block/xen-blkback | |
| parent | 7c77474b2d22176d2bfb592ec74e0f2cb71352c9 (diff) | |
| download | linux-871997bc9e423f05c7da7c9178e62dde5df2a7f8.tar.xz | |
xen-blkback: fix error handling in xen_blkbk_map()
The function uses a goto-based loop, which may lead to an earlier error
getting discarded by a later iteration. Exit this ad-hoc loop when an
error was encountered.
The out-of-memory error path additionally fails to fill a structure
field looked at by xen_blkbk_unmap_prepare() before inspecting the
handle which does get properly set (to BLKBACK_INVALID_HANDLE).
Since the earlier exiting from the ad-hoc loop requires the same field
filling (invalidation) as that on the out-of-memory path, fold both
paths. While doing so, drop the pr_alert(), as extra log messages aren't
going to help the situation (the kernel will log oom conditions already
anyway).
This is XSA-365.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/block/xen-blkback')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index ee62b3c0b55a..da16121140ca 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -794,8 +794,13 @@ again: pages[i]->persistent_gnt = persistent_gnt; } else { if (gnttab_page_cache_get(&ring->free_pages, - &pages[i]->page)) - goto out_of_memory; + &pages[i]->page)) { + gnttab_page_cache_put(&ring->free_pages, + pages_to_gnt, + segs_to_map); + ret = -ENOMEM; + goto out; + } addr = vaddr(pages[i]->page); pages_to_gnt[segs_to_map] = pages[i]->page; pages[i]->persistent_gnt = NULL; @@ -880,17 +885,18 @@ next: } segs_to_map = 0; last_map = map_until; - if (map_until != num) + if (!ret && map_until != num) goto again; - return ret; - -out_of_memory: - pr_alert("%s: out of memory\n", __func__); - gnttab_page_cache_put(&ring->free_pages, pages_to_gnt, segs_to_map); - for (i = last_map; i < num; i++) +out: + for (i = last_map; i < num; i++) { + /* Don't zap current batch's valid persistent grants. */ + if(i >= last_map + segs_to_map) + pages[i]->persistent_gnt = NULL; pages[i]->handle = BLKBACK_INVALID_HANDLE; - return -ENOMEM; + } + + return ret; } static int xen_blkbk_map_seg(struct pending_req *pending_req) |