Re: [PATCH 2/3] xen-blkfront: rm BUG_ON(info->feature_persistent) in blkif_free
On 07/22/2015 12:43 PM, Bob Liu wrote:
>
> On 07/21/2015 05:25 PM, Roger Pau Monné wrote:
>> El 21/07/15 a les 5.30, Bob Liu ha escrit:
>>> This BUG_ON() in blkif_free() is incorrect, because indirect page can be
>>> added
>>> to list info->indirect_pages in blkif_completion() no matter
>>> feature_persistent
>>> is true or false.
>>>
>>> Signed-off-by: Bob Liu
>>
>> Acked-by: Roger Pau Monné
>>
>> This was probably an oversight from when blkif_completion was changed to
>> check for gnttab_query_foreign_access. It should be backported to stable
>> trees.
>>
>
> Sorry, this patch is buggy and I haven't figure out why.
>
> general protection fault: [#1] SMP
> Modules linked in:
> CPU: 0 PID: 39 Comm: xenwatch Tainted: GW
> 4.1.0-rc3-3-g718cf80-dirty #67
> Hardware name: Xen HVM domU, BIOS 4.5.0-rc 11/23/2014
> task: 880283f4eca0 ti: 880283fb4000 task.ti: 880283fb4000
> RIP: 0010:[] [] blkif_free+0x162/0x5a9
> RSP: 0018:880283fb7c48 EFLAGS: 00010087
> RAX: dead00200200 RBX: 88014140 RCX:
> RDX: dead00100100 RSI: dead00100100 RDI: 88028f418bb8
> RBP: 880283fb7ca8 R08: dead00200200 R09: 0001
> R10: 0001 R11: R12: 8801414481c8
> R13: dead001000e0 R14: 8801414481b8 R15: ea00
> FS: () GS:88028f40() knlGS:
> CS: 0010 DS: ES: CR0: 80050033
> CR2: 01582e08 CR3: 00013345b000 CR4: 001406f0
> Stack:
> 880023aa8420 0286 880283fb7cb7 880023aa8420
> 8800363fe240 81862c50 880283fb7ce8 880023aa8440
> 8187 880023aa8400 88014140 88014148
> Call Trace:
> [] blkfront_remove+0x4c/0xff
> [] xenbus_dev_remove+0x76/0xb0
> [] __device_release_driver+0x84/0xf8
> [] device_release_driver+0x1e/0x2b
> [] bus_remove_device+0x12c/0x141
> [] device_del+0x161/0x1e5
> [] ? xenbus_thread+0x239/0x239
> [] device_unregister+0x43/0x4f
> [] xenbus_dev_changed+0x82/0x17f
> [] ? xenbus_otherend_changed+0xf0/0xff
> [] frontend_changed+0x43/0x48
> [] xenwatch_thread+0xf9/0x127
> [] ? add_wait_queue+0x44/0x44
> [] kthread+0xcd/0xd5
> [] ? alloc_pid+0xe8/0x492
> [] ? kthread_freezable_should_stop+0x48/0x48
> [] ret_from_fork+0x42/0x70
> [] ? kthread_freezable_should_stop+0x48/0x48
> Code: 04 00 4c 8b 28 48 8d 78 e0 49 83 ed 20 eb 3d 48 8b 47 28 48 8b 57 20 48
> be 00 01 10 00 00 00 ad de 49 b8 00 02 20 00 00 00 ad de <48> 89 42 08 48 89
> 10 48 89 77 20 4c 89 47 28 31 f6 e8 26 7d cf
> RIP [] blkif_free+0x162/0x5a9
> RSP
> ---[ end trace 5321d7f1ef8414d0 ]---
>
The right fix should be:
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1124,8 +1124,10 @@ static void blkif_completion(struct blk_shadow *s,
struct blkfront_info *info,
* Add the used indirect page back to the list
of
* available pages for indirect grefs.
*/
- indirect_page =
pfn_to_page(s->indirect_grants[i]->pfn);
- list_add(&indirect_page->lru,
&info->indirect_pages);
+ if (!info->feature_persistent) {
+ indirect_page =
pfn_to_page(s->indirect_grants[i]->pfn);
+ list_add(&indirect_page->lru,
&info->indirect_pages);
+ }
s->indirect_grants[i]->gref = GRANT_INVALID_REF;
list_add_tail(&s->indirect_grants[i]->node,
&info->grants);
}
--
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Re: [PATCH 2/3] xen-blkfront: rm BUG_ON(info->feature_persistent) in blkif_free
On 07/21/2015 05:25 PM, Roger Pau Monné wrote: > El 21/07/15 a les 5.30, Bob Liu ha escrit: >> This BUG_ON() in blkif_free() is incorrect, because indirect page can be >> added >> to list info->indirect_pages in blkif_completion() no matter >> feature_persistent >> is true or false. >> >> Signed-off-by: Bob Liu > > Acked-by: Roger Pau Monné > > This was probably an oversight from when blkif_completion was changed to > check for gnttab_query_foreign_access. It should be backported to stable > trees. > Sorry, this patch is buggy and I haven't figure out why. general protection fault: [#1] SMP Modules linked in: CPU: 0 PID: 39 Comm: xenwatch Tainted: GW 4.1.0-rc3-3-g718cf80-dirty #67 Hardware name: Xen HVM domU, BIOS 4.5.0-rc 11/23/2014 task: 880283f4eca0 ti: 880283fb4000 task.ti: 880283fb4000 RIP: 0010:[] [] blkif_free+0x162/0x5a9 RSP: 0018:880283fb7c48 EFLAGS: 00010087 RAX: dead00200200 RBX: 88014140 RCX: RDX: dead00100100 RSI: dead00100100 RDI: 88028f418bb8 RBP: 880283fb7ca8 R08: dead00200200 R09: 0001 R10: 0001 R11: R12: 8801414481c8 R13: dead001000e0 R14: 8801414481b8 R15: ea00 FS: () GS:88028f40() knlGS: CS: 0010 DS: ES: CR0: 80050033 CR2: 01582e08 CR3: 00013345b000 CR4: 001406f0 Stack: 880023aa8420 0286 880283fb7cb7 880023aa8420 8800363fe240 81862c50 880283fb7ce8 880023aa8440 8187 880023aa8400 88014140 88014148 Call Trace: [] blkfront_remove+0x4c/0xff [] xenbus_dev_remove+0x76/0xb0 [] __device_release_driver+0x84/0xf8 [] device_release_driver+0x1e/0x2b [] bus_remove_device+0x12c/0x141 [] device_del+0x161/0x1e5 [] ? xenbus_thread+0x239/0x239 [] device_unregister+0x43/0x4f [] xenbus_dev_changed+0x82/0x17f [] ? xenbus_otherend_changed+0xf0/0xff [] frontend_changed+0x43/0x48 [] xenwatch_thread+0xf9/0x127 [] ? add_wait_queue+0x44/0x44 [] kthread+0xcd/0xd5 [] ? alloc_pid+0xe8/0x492 [] ? kthread_freezable_should_stop+0x48/0x48 [] ret_from_fork+0x42/0x70 [] ? kthread_freezable_should_stop+0x48/0x48 Code: 04 00 4c 8b 28 48 8d 78 e0 49 83 ed 20 eb 3d 48 8b 47 28 48 8b 57 20 48 be 00 01 10 00 00 00 ad de 49 b8 00 02 20 00 00 00 ad de <48> 89 42 08 48 89 10 48 89 77 20 4c 89 47 28 31 f6 e8 26 7d cf RIP [] blkif_free+0x162/0x5a9 RSP ---[ end trace 5321d7f1ef8414d0 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 2/3] xen-blkfront: rm BUG_ON(info->feature_persistent) in blkif_free
El 21/07/15 a les 5.30, Bob Liu ha escrit: > This BUG_ON() in blkif_free() is incorrect, because indirect page can be added > to list info->indirect_pages in blkif_completion() no matter > feature_persistent > is true or false. > > Signed-off-by: Bob Liu Acked-by: Roger Pau Monné This was probably an oversight from when blkif_completion was changed to check for gnttab_query_foreign_access. It should be backported to stable trees. Roger. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 2/3] xen-blkfront: rm BUG_ON(info->feature_persistent) in blkif_free
This BUG_ON() in blkif_free() is incorrect, because indirect page can be added
to list info->indirect_pages in blkif_completion() no matter feature_persistent
is true or false.
Signed-off-by: Bob Liu
---
drivers/block/xen-blkfront.c |1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index e266d17..c98fcd0 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -986,7 +986,6 @@ static void blkif_free(struct blkfront_info *info, int
suspend)
if (!list_empty(&info->indirect_pages)) {
struct page *indirect_page, *n;
- BUG_ON(info->feature_persistent);
list_for_each_entry_safe(indirect_page, n,
&info->indirect_pages, lru) {
list_del(&indirect_page->lru);
__free_page(indirect_page);
--
1.7.10.4
--
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