From: Naoya Horiguchi <naoya.horiguchi@linux.dev>
To: Yang Shi <shy828301@gmail.com>
Cc: "HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"Hugh Dickins" <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Peter Xu" <peterx@redhat.com>,
"Oscar Salvador" <osalvador@suse.de>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linux MM" <linux-mm@kvack.org>,
"Linux FS-devel Mailing List" <linux-fsdevel@vger.kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [v4 PATCH 5/6] mm: shmem: don't truncate page if memory failure happens
Date: Wed, 20 Oct 2021 07:30:07 +0900 [thread overview]
Message-ID: <20211019223007.GA2324358@u2004> (raw)
In-Reply-To: <CAHbLzkqfbsnUtxZCs0JK_b_G95id1D0q=c_hCuuZe7i6q_6oDQ@mail.gmail.com>
On Tue, Oct 19, 2021 at 10:29:51AM -0700, Yang Shi wrote:
> On Mon, Oct 18, 2021 at 10:52 PM Naoya Horiguchi
> <naoya.horiguchi@linux.dev> wrote:
> >
> > On Thu, Oct 14, 2021 at 12:16:14PM -0700, Yang Shi wrote:
...
> > > @@ -2466,7 +2467,15 @@ shmem_write_begin(struct file *file, struct address_space *mapping,
> > > return -EPERM;
> > > }
> > >
> > > - return shmem_getpage(inode, index, pagep, SGP_WRITE);
> > > + ret = shmem_getpage(inode, index, pagep, SGP_WRITE);
> > > +
> > > + if (*pagep && PageHWPoison(*pagep)) {
> >
> > shmem_getpage() could return with pagep == NULL, so you need check ret first
> > to avoid NULL pointer dereference.
>
> Realy? IIUC pagep can't be NULL. It is a pointer's pointer passed in
> by the caller, for example, generic_perform_write(). Of course,
> "*pagep" could be NULL.
Oh, I simply missed this. You're right. Please ignore my comment on this.
- Naoya Horiguchi
next prev parent reply other threads:[~2021-10-19 22:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 19:16 [RFC v4 PATCH 0/6] Solve silent data loss caused by poisoned page cache (shmem/tmpfs) Yang Shi
2021-10-14 19:16 ` [v4 PATCH 1/6] mm: hwpoison: remove the unnecessary THP check Yang Shi
2021-10-14 19:16 ` [v4 PATCH 2/6] mm: filemap: check if THP has hwpoisoned subpage for PMD page fault Yang Shi
2021-10-19 5:50 ` Naoya Horiguchi
2021-10-19 17:13 ` Yang Shi
2021-10-14 19:16 ` [v4 PATCH 3/6] mm: filemap: coding style cleanup for filemap_map_pmd() Yang Shi
2021-10-19 5:51 ` Naoya Horiguchi
2021-10-14 19:16 ` [v4 PATCH 4/6] mm: hwpoison: refactor refcount check handling Yang Shi
2021-10-14 19:16 ` [v4 PATCH 5/6] mm: shmem: don't truncate page if memory failure happens Yang Shi
2021-10-19 5:52 ` Naoya Horiguchi
2021-10-19 17:29 ` Yang Shi
2021-10-19 22:30 ` Naoya Horiguchi [this message]
2021-10-20 18:32 ` Yang Shi
2021-10-14 19:16 ` [v4 PATCH 6/6] mm: hwpoison: handle non-anonymous THP correctly Yang Shi
2021-10-15 20:28 ` [RFC v4 PATCH 0/6] Solve silent data loss caused by poisoned page cache (shmem/tmpfs) Andrew Morton
2021-10-15 21:48 ` Yang Shi
2021-10-19 5:53 ` Naoya Horiguchi
2021-10-19 17:32 ` Yang Shi
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