From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: drivers/scsi/sg.c: mark VMA as VM_IO to prevent migration
Reduced testcase:
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <numaif.h>
#define SIZE 0x2000
int main()
{
int fd;
void *p;
fd = open("/dev/sg0", O_RDWR);
p = mmap(NULL, SIZE, PROT_EXEC, MAP_PRIVATE | MAP_LOCKED, fd, 0);
mbind(p, SIZE, 0, NULL, 0, MPOL_MF_MOVE);
return 0;
}
We shouldn't try to migrate pages in sg VMA as we don't have a way to
update Sg_scatter_hold::pages accordingly from mm core.
Let's mark the VMA as VM_IO to indicate to mm core that the VMA is
not migratable.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Doug Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Shiraz Hashim <shashim@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: syzkaller <syzkaller@xxxxxxxxxxxxxxxx>
Cc: Kostya Serebryany <kcc@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/scsi/sg.c~drivers-scsi-sgc-mark-vma-as-vm_io-to-prevent-migration drivers/scsi/sg.c
--- a/drivers/scsi/sg.c~drivers-scsi-sgc-mark-vma-as-vm_io-to-prevent-migration
+++ a/drivers/scsi/sg.c
@@ -1261,7 +1261,7 @@ sg_mmap(struct file *filp, struct vm_are
}
sfp->mmap_called = 1;
- vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_private_data = sfp;
vma->vm_ops = &sg_mmap_vm_ops;
return 0;
_
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