On Mon, Sep 14, 2020 at 03:49:43PM +0530, Naresh Kamboju wrote:
> While running LTP fs on qemu x86 and qemu_i386 these kernel BUGs noticed.

I actually sent the fix for this a couple of days ago [1], but I think Andrew
overlooked it while constructing the -mm tree.  Here's a fix you can
apply to the -mm tree:

[1] https://lore.kernel.org/linux-mm/20200912032042.ga6...@casper.infradead.org/

diff --git a/mm/shmem.c b/mm/shmem.c
index d2a46ef7df43..58bc9e326d0d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1793,7 +1793,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t 
index,
        struct mm_struct *charge_mm;
        struct page *page;
        enum sgp_type sgp_huge = sgp;
-       pgoff_t hindex;
+       pgoff_t hindex = index;
        int error;
        int once = 0;
        int alloced = 0;
@@ -1822,6 +1822,8 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t 
index,
                return error;
        }
 
+       if (page)
+               hindex = page->index;
        if (page && sgp == SGP_WRITE)
                mark_page_accessed(page);
 
@@ -1832,6 +1834,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t 
index,
                unlock_page(page);
                put_page(page);
                page = NULL;
+               hindex = index;
        }
        if (page || sgp == SGP_READ)
                goto out;
@@ -1982,7 +1985,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t 
index,
                goto unlock;
        }
 out:
-       *pagep = page + index - page->index;
+       *pagep = page + index - hindex;
        return 0;
 
        /*

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