From: Yu Zhao <yuzhao@google.com>
To: Peter Xu <peterx@redhat.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
David Hildenbrand <david@redhat.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] mm/mprotect: Only reference swap pfn page if type match
Date: Tue, 23 Aug 2022 16:44:51 -0600 [thread overview]
Message-ID: <CAOUHufbcxL5GcqQFJHEzsLTV8htAuZ1qucRGBhNQBg65Q4JYuw@mail.gmail.com> (raw)
In-Reply-To: <20220823221138.45602-1-peterx@redhat.com>
On Tue, Aug 23, 2022 at 4:11 PM Peter Xu <peterx@redhat.com> wrote:
>
> Yu Zhao reported a bug after the commit "mm/swap: Add swp_offset_pfn() to
> fetch PFN from swap entry" added a check in swp_offset_pfn() for swap type [1]:
>
> kernel BUG at include/linux/swapops.h:117!
> CPU: 46 PID: 5245 Comm: EventManager_De Tainted: G S O L 6.0.0-dbg-DEV #2
> RIP: 0010:pfn_swap_entry_to_page+0x72/0xf0
> Code: c6 48 8b 36 48 83 fe ff 74 53 48 01 d1 48 83 c1 08 48 8b 09 f6
> c1 01 75 7b 66 90 48 89 c1 48 8b 09 f6 c1 01 74 74 5d c3 eb 9e <0f> 0b
> 48 ba ff ff ff ff 03 00 00 00 eb ae a9 ff 0f 00 00 75 13 48
> RSP: 0018:ffffa59e73fabb80 EFLAGS: 00010282
> RAX: 00000000ffffffe8 RBX: 0c00000000000000 RCX: ffffcd5440000000
> RDX: 1ffffffffff7a80a RSI: 0000000000000000 RDI: 0c0000000000042b
> RBP: ffffa59e73fabb80 R08: ffff9965ca6e8bb8 R09: 0000000000000000
> R10: ffffffffa5a2f62d R11: 0000030b372e9fff R12: ffff997b79db5738
> R13: 000000000000042b R14: 0c0000000000042b R15: 1ffffffffff7a80a
> FS: 00007f549d1bb700(0000) GS:ffff99d3cf680000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000440d035b3180 CR3: 0000002243176004 CR4: 00000000003706e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> change_pte_range+0x36e/0x880
> change_p4d_range+0x2e8/0x670
> change_protection_range+0x14e/0x2c0
> mprotect_fixup+0x1ee/0x330
> do_mprotect_pkey+0x34c/0x440
> __x64_sys_mprotect+0x1d/0x30
>
> It triggers because pfn_swap_entry_to_page() could be called upon e.g. a
> genuine swap entry.
>
> Fix it by only calling it when it's a write migration entry where the page*
> is used.
>
> [1] https://lore.kernel.org/lkml/CAOUHufaVC2Za-p8m0aiHw6YkheDcrO-C3wRGixwDS32VTS+k1w@mail.gmail.com/
>
> Fixes: 6c287605fd56 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive")
> Cc: David Hildenbrand <david@redhat.com>
> Cc: <stable@vger.kernel.org>
> Reported-by: Yu Zhao <yuzhao@google.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
Thanks for the quick turnaround!
Tested-by: Yu Zhao <yuzhao@google.com>
next prev parent reply other threads:[~2022-08-23 22:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 22:11 [PATCH] mm/mprotect: Only reference swap pfn page if type match Peter Xu
2022-08-23 22:44 ` Yu Zhao [this message]
2022-08-24 6:58 ` David Hildenbrand
2022-08-26 10:49 ` David Hildenbrand
2022-08-26 14:25 ` Peter Xu
2022-08-26 14:39 ` David Hildenbrand
2022-08-26 16:04 ` Peter Xu
2022-08-26 16:35 ` David Hildenbrand
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