lkml.org 
[lkml]   [2022]   [Jul]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.4] Ignore failure to unmap -1
Date
The error paths of gntdev_mmap() can call unmap_grant_pages() even
though not all of the pages have been successfully mapped. This will
trigger the WARN_ON()s in __unmap_grant_pages_done(). The number of
warnings can be very large; I have observed thousands of lines of
warnings in the systemd journal.

Avoid this problem by only warning on unmapping failure if the handle
being unmapped is not -1. The handle field of any page that was not
successfully mapped will be -1, so this catches all cases wherr
unmapping can legitimately fail.

Suggested-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Fixes: ee25841221c1 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
---
drivers/xen/gntdev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index f464793477650e631c8928e85c1990c5964c2e94..bba849e5d8a7b4d54925b842fbe3c6792e0f0214 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -413,7 +413,8 @@ static void __unmap_grant_pages_done(int result,
unsigned int offset = data->unmap_ops - map->unmap_ops;

for (i = 0; i < data->count; i++) {
- WARN_ON(map->unmap_ops[offset+i].status);
+ WARN_ON(map->unmap_ops[offset+i].status &&
+ map->unmap_ops[offset+i].handle != -1);
pr_debug("unmap handle=%d st=%d\n",
map->unmap_ops[offset+i].handle,
map->unmap_ops[offset+i].status);
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
\
 
 \ /
  Last update: 2022-07-08 18:40    [W:0.166 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site