Re: [PATCH] mm/memory: Return vm_fault_t result from migrate_to_ram() callback

[Felix Kuehling]

Am 2022-11-14 um 11:41 schrieb David Hildenbrand:

On 14.11.22 12:55, Alistair Popple wrote:

The migrate_to_ram() callback should always succeed, but in rare cases
can fail usually returning VM_FAULT_SIGBUS. Commit 16ce101db85d
("mm/memory.c: fix race when faulting a device private page")
incorrectly stopped passing the return code up the stack. Fix this by
setting the ret variable, restoring the previous behaviour on
migrate_to_ram() failure.

Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device 
private page")

Signed-off-by: Alistair Popple 
Cc: Ralph Campbell 
Cc: John Hubbard 
Cc: Alex Sierra 
Cc: Ben Skeggs 
Cc: Felix Kuehling 
Cc: Lyude Paul 
Cc: Jason Gunthorpe 
Cc: Michael Ellerman 


Reviewed-by: Felix Kuehling 




---

Hi Andrew, I noticed my series needs another small fix which I'm
hoping you can apply for v6.1-rcX. Thanks (and sorry for not catching
this sooner).
---
  mm/memory.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index f88c351aecd4..8a6d5c823f91 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3763,7 +3763,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
   */
  get_page(vmf->page);
  pte_unmap_unlock(vmf->pte, vmf->ptl);
- vmf->page->pgmap->ops->migrate_to_ram(vmf);
+    ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
  put_page(vmf->page);
  } else if (is_hwpoison_entry(entry)) {
  ret = VM_FAULT_HWPOISON;



Acked-by: David Hildenbrand 

Re: [PATCH] mm/memory: Return vm_fault_t result from migrate_to_ram() callback

[David Hildenbrand]

On 14.11.22 12:55, Alistair Popple wrote:

The migrate_to_ram() callback should always succeed, but in rare cases
can fail usually returning VM_FAULT_SIGBUS. Commit 16ce101db85d
("mm/memory.c: fix race when faulting a device private page")
incorrectly stopped passing the return code up the stack. Fix this by
setting the ret variable, restoring the previous behaviour on
migrate_to_ram() failure.

Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device private 
page")
Signed-off-by: Alistair Popple 
Cc: Ralph Campbell 
Cc: John Hubbard 
Cc: Alex Sierra 
Cc: Ben Skeggs 
Cc: Felix Kuehling 
Cc: Lyude Paul 
Cc: Jason Gunthorpe 
Cc: Michael Ellerman 

---

Hi Andrew, I noticed my series needs another small fix which I'm
hoping you can apply for v6.1-rcX. Thanks (and sorry for not catching
this sooner).
---
  mm/memory.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index f88c351aecd4..8a6d5c823f91 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3763,7 +3763,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 */
get_page(vmf->page);
pte_unmap_unlock(vmf->pte, vmf->ptl);
-   vmf->page->pgmap->ops->migrate_to_ram(vmf);
+   ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
put_page(vmf->page);
} else if (is_hwpoison_entry(entry)) {
ret = VM_FAULT_HWPOISON;



Acked-by: David Hildenbrand 

--
Thanks,

David / dhildenb

[PATCH] mm/memory: Return vm_fault_t result from migrate_to_ram() callback

[Alistair Popple]

The migrate_to_ram() callback should always succeed, but in rare cases
can fail usually returning VM_FAULT_SIGBUS. Commit 16ce101db85d
("mm/memory.c: fix race when faulting a device private page")
incorrectly stopped passing the return code up the stack. Fix this by
setting the ret variable, restoring the previous behaviour on
migrate_to_ram() failure.

Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device private 
page")
Signed-off-by: Alistair Popple 
Cc: Ralph Campbell 
Cc: John Hubbard 
Cc: Alex Sierra 
Cc: Ben Skeggs 
Cc: Felix Kuehling 
Cc: Lyude Paul 
Cc: Jason Gunthorpe 
Cc: Michael Ellerman 

---

Hi Andrew, I noticed my series needs another small fix which I'm
hoping you can apply for v6.1-rcX. Thanks (and sorry for not catching
this sooner).
---
 mm/memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index f88c351aecd4..8a6d5c823f91 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3763,7 +3763,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 */
get_page(vmf->page);
pte_unmap_unlock(vmf->pte, vmf->ptl);
-   vmf->page->pgmap->ops->migrate_to_ram(vmf);
+   ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
put_page(vmf->page);
} else if (is_hwpoison_entry(entry)) {
ret = VM_FAULT_HWPOISON;
-- 
2.35.1