* Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE")
@ 2022-07-23 3:44 Demi Marie Obenour
2022-07-23 3:44 ` [PATCH 4.9] Ignore failure to unmap -1 Demi Marie Obenour
2022-07-23 14:52 ` Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Greg Kroah-Hartman
0 siblings, 2 replies; 4+ messages in thread
From: Demi Marie Obenour @ 2022-07-23 3:44 UTC (permalink / raw)
To: Boris Ostrovsky, Juergen Gross, Stefano Stabellini, Greg Kroah-Hartman
Cc: Demi Marie Obenour, xen-devel, linux-kernel, stable
This series backports upstream commit 166d3863231667c4f64dee72b77d1102cdfad11f
to all supported stable kernel trees.
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 4.9] Ignore failure to unmap -1
2022-07-23 3:44 Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Demi Marie Obenour
@ 2022-07-23 3:44 ` Demi Marie Obenour
2022-07-23 14:52 ` Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Greg Kroah-Hartman
1 sibling, 0 replies; 4+ messages in thread
From: Demi Marie Obenour @ 2022-07-23 3:44 UTC (permalink / raw)
To: Boris Ostrovsky, Juergen Gross, Stefano Stabellini, Greg Kroah-Hartman
Cc: Demi Marie Obenour, xen-devel, linux-kernel, stable
[ Upstream commit 166d3863231667c4f64dee72b77d1102cdfad11f ]
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 where
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: 36cd49b071fc ("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 2c3248e71e9c1a3e032b847d177b02855cdda1a1..a6585854a85fc6fffc16c3498ba73fbee84ad6ca 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -390,7 +390,8 @@ 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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE")
2022-07-23 3:44 Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Demi Marie Obenour
2022-07-23 3:44 ` [PATCH 4.9] Ignore failure to unmap -1 Demi Marie Obenour
@ 2022-07-23 14:52 ` Greg Kroah-Hartman
1 sibling, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2022-07-23 14:52 UTC (permalink / raw)
To: Demi Marie Obenour
Cc: Boris Ostrovsky, Juergen Gross, Stefano Stabellini, xen-devel,
linux-kernel, stable
On Fri, Jul 22, 2022 at 11:44:10PM -0400, Demi Marie Obenour wrote:
> This series backports upstream commit 166d3863231667c4f64dee72b77d1102cdfad11f
> to all supported stable kernel trees.
All now queued up, thanks.
greg k-h
^ permalink raw reply [flat|nested] 4+ messages in thread
* Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE")
@ 2022-07-18 18:08 Demi Marie Obenour
0 siblings, 0 replies; 4+ messages in thread
From: Demi Marie Obenour @ 2022-07-18 18:08 UTC (permalink / raw)
To: Boris Ostrovsky, Juergen Gross, Stefano Stabellini, Greg Kroah-Hartman
Cc: Demi Marie Obenour, xen-devel, linux-kernel, stable
This series backports upstream commit 166d3863231667c4f64dee72b77d1102cdfad11f
to all supported stable kernel trees.
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-07-23 3:44 Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Demi Marie Obenour
2022-07-23 3:44 ` [PATCH 4.9] Ignore failure to unmap -1 Demi Marie Obenour
2022-07-23 14:52 ` Backport of 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") Greg Kroah-Hartman
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