From: Rongwei Wang <rongwei.wang@linux.alibaba.com>
To: willy@infradead.org, hughd@google.com, song@kernel.org,
shy828301@gmail.com
Cc: akpm@linux-foundation.org, william.kucharski@oracle.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] mm, thp: lock filemap when truncating page cache
Date: Wed, 13 Oct 2021 15:55:05 +0800 [thread overview]
Message-ID: <60de628a-82dd-24d6-4f89-00a2d61ce628@linux.alibaba.com> (raw)
In-Reply-To: <20211011022241.97072-2-rongwei.wang@linux.alibaba.com>
Hello
I see this patch has not been replied by all. I'm not sure whether this
patch has passed review or the status needs to be modified.
Thanks!
On 10/11/21 10:22 AM, Rongwei Wang wrote:
> Transparent huge page has supported read-only non-shmem files. The file-
> backed THP is collapsed by khugepaged and truncated when written (for
> shared libraries).
>
> However, there is a race when multiple writers truncate the same page
> cache concurrently.
>
> In that case, subpage(s) of file THP can be revealed by find_get_entry
> in truncate_inode_pages_range, which will trigger PageTail BUG_ON in
> truncate_inode_page, as follows.
>
> page:000000009e420ff2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff pfn:0x50c3ff
> head:0000000075ff816d order:9 compound_mapcount:0 compound_pincount:0
> flags: 0x37fffe0000010815(locked|uptodate|lru|arch_1|head)
> raw: 37fffe0000000000 fffffe0013108001 dead000000000122 dead000000000400
> raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
> head: 37fffe0000010815 fffffe001066bd48 ffff000404183c20 0000000000000000
> head: 0000000000000600 0000000000000000 00000001ffffffff ffff000c0345a000
> page dumped because: VM_BUG_ON_PAGE(PageTail(page))
> ------------[ cut here ]------------
> kernel BUG at mm/truncate.c:213!
> Internal error: Oops - BUG: 0 [#1] SMP
> Modules linked in: xfs(E) libcrc32c(E) rfkill(E) ...
> CPU: 14 PID: 11394 Comm: check_madvise_d Kdump: ...
> Hardware name: ECS, BIOS 0.0.0 02/06/2015
> pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
> pc : truncate_inode_page+0x64/0x70
> lr : truncate_inode_page+0x64/0x70
> sp : ffff80001b60b900
> x29: ffff80001b60b900 x28: 00000000000007ff
> x27: ffff80001b60b9a0 x26: 0000000000000000
> x25: 000000000000000f x24: ffff80001b60b9a0
> x23: ffff80001b60ba18 x22: ffff0001e0999ea8
> x21: ffff0000c21db300 x20: ffffffffffffffff
> x19: fffffe001310ffc0 x18: 0000000000000020
> x17: 0000000000000000 x16: 0000000000000000
> x15: ffff0000c21db960 x14: 3030306666666620
> x13: 6666666666666666 x12: 3130303030303030
> x11: ffff8000117b69b8 x10: 00000000ffff8000
> x9 : ffff80001012690c x8 : 0000000000000000
> x7 : ffff8000114f69b8 x6 : 0000000000017ffd
> x5 : ffff0007fffbcbc8 x4 : ffff80001b60b5c0
> x3 : 0000000000000001 x2 : 0000000000000000
> x1 : 0000000000000000 x0 : 0000000000000000
> Call trace:
> truncate_inode_page+0x64/0x70
> truncate_inode_pages_range+0x550/0x7e4
> truncate_pagecache+0x58/0x80
> do_dentry_open+0x1e4/0x3c0
> vfs_open+0x38/0x44
> do_open+0x1f0/0x310
> path_openat+0x114/0x1dc
> do_filp_open+0x84/0x134
> do_sys_openat2+0xbc/0x164
> __arm64_sys_openat+0x74/0xc0
> el0_svc_common.constprop.0+0x88/0x220
> do_el0_svc+0x30/0xa0
> el0_svc+0x20/0x30
> el0_sync_handler+0x1a4/0x1b0
> el0_sync+0x180/0x1c0
> Code: aa0103e0 900061e1 910ec021 9400d300 (d4210000)
> ---[ end trace f70cdb42cb7c2d42 ]---
> Kernel panic - not syncing: Oops - BUG: Fatal exception
>
> This patch mainly to lock filemap when one enter truncate_pagecache(),
> avoiding truncating the same page cache concurrently.
>
> Fixes: eb6ecbed0aa2 ("mm, thp: relax the VM_DENYWRITE constraint on file-backed THPs")
> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Tested-by: Song Liu <song@kernel.org>
> Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
> Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
> ---
> fs/open.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/open.c b/fs/open.c
> index daa324606a41..9ec3cfca3b1a 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -856,8 +856,11 @@ static int do_dentry_open(struct file *f,
> * of THPs into the page cache will fail.
> */
> smp_mb();
> - if (filemap_nr_thps(inode->i_mapping))
> + if (filemap_nr_thps(inode->i_mapping)) {
> + filemap_invalidate_lock(inode->i_mapping);
> truncate_pagecache(inode, 0);
> + filemap_invalidate_unlock(inode->i_mapping);
> + }
> }
>
> return 0;
>
next prev parent reply other threads:[~2021-10-13 7:55 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-06 12:11 [PATCH 0/2] mm, thp: fix file-backed THP race in collapse_file Rongwei Wang
2021-09-06 12:11 ` [PATCH 1/2] mm, thp: check page mapping when truncating page cache Rongwei Wang
2021-09-07 2:49 ` Yu Xu
2021-09-07 18:08 ` Yang Shi
[not found] ` <38AF4DC8-5E6F-4568-B2E3-0434BD847BC9@linux.alibaba.com>
2021-09-08 21:48 ` Yang Shi
2021-09-13 14:49 ` [mm, thp] 20753096b6: BUG:unable_to_handle_page_fault_for_address kernel test robot
2021-09-06 12:12 ` [PATCH 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-09-07 16:56 ` Yang Shi
[not found] ` <44BE85B4-692C-41E8-B5A0-C1E0B0272ACD@linux.alibaba.com>
2021-09-08 21:51 ` Yang Shi
2021-09-22 7:06 ` [PATCH v2 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-09-22 7:06 ` [PATCH v2 1/2] mm, thp: check page mapping when truncating page cache Rongwei Wang
2021-09-22 11:37 ` Matthew Wilcox
2021-09-22 17:04 ` Rongwei Wang
2021-09-24 2:43 ` Andrew Morton
2021-09-24 3:08 ` Yang Shi
2021-09-24 3:35 ` Rongwei Wang
2021-09-24 7:12 ` Rongwei Wang
2021-09-27 22:24 ` Song Liu
2021-09-28 12:06 ` Matthew Wilcox
2021-09-28 16:59 ` Song Liu
2021-09-28 16:20 ` Rongwei Wang
2021-09-29 7:14 ` Song Liu
2021-09-29 7:50 ` Rongwei Wang
2021-09-29 16:59 ` Song Liu
2021-09-29 17:55 ` Matthew Wilcox
2021-09-29 23:41 ` Song Liu
2021-09-30 0:00 ` Matthew Wilcox
2021-09-30 0:41 ` Song Liu
2021-09-30 2:14 ` Rongwei Wang
2021-10-04 17:26 ` Rongwei Wang
2021-10-04 19:05 ` Matthew Wilcox
2021-10-05 1:58 ` Rongwei Wang
2021-10-04 20:26 ` Song Liu
2021-10-05 2:58 ` Hugh Dickins
2021-10-05 3:07 ` Matthew Wilcox
2021-10-05 9:03 ` Rongwei Wang
2021-09-30 1:54 ` Rongwei Wang
2021-09-30 3:26 ` Song Liu
2021-09-30 5:24 ` Hugh Dickins
2021-09-30 15:28 ` Matthew Wilcox
2021-09-30 16:49 ` Hugh Dickins
2021-09-30 17:39 ` Yang Shi
2021-10-02 17:08 ` Matthew Wilcox
2021-10-04 18:28 ` Yang Shi
2021-10-04 19:31 ` Matthew Wilcox
2021-10-05 2:26 ` Hugh Dickins
2021-10-02 2:22 ` Rongwei Wang
2021-09-22 7:06 ` [PATCH v2 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 1/2] mm, thp: lock filemap when truncating page cache Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-06 2:41 ` Matthew Wilcox
2021-10-06 8:39 ` Rongwei Wang
2021-10-06 17:58 ` Yang Shi
2021-10-11 2:22 ` [PATCH v4 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-10-11 2:22 ` [PATCH v4 1/2] mm, thp: lock filemap when truncating page cache Rongwei Wang
2021-10-13 7:55 ` Rongwei Wang [this message]
2021-10-11 2:22 ` [PATCH v4 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-11 3:08 ` Matthew Wilcox
2021-10-11 3:22 ` Rongwei Wang
2021-10-11 5:08 ` [PATCH v4 RESEND " Rongwei Wang
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