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66f28ffb38
When performing a right split on a folio, the split_at2 may point to a
not-present page if the offset + length equals the original folio size,
which will trigger the following error:
BUG: unable to handle page fault for address: ffffea0006000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 143ffb9067 P4D 143ffb9067 PUD 143ffb8067 PMD 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 0 UID: 0 PID: 502640 Comm: fsx Not tainted 6.15.0-rc3-gc6156189fc6b #889 PR
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/4
RIP: 0010:truncate_inode_partial_folio+0x208/0x620
Code: ff 03 48 01 da e8 78 7e 13 00 48 83 05 10 b5 5a 0c 01 85 c0 0f 85 1c 02 001
RSP: 0018:ffffc90005bafab0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffea0005ffff00 RCX: 0000000000000002
RDX: 000000000000000c RSI: 0000000000013975 RDI: ffffc90005bafa30
RBP: ffffea0006000000 R08: 0000000000000000 R09: 00000000000009bf
R10: 00000000000007e0 R11: 0000000000000000 R12: 0000000000001633
R13: 0000000000000000 R14: ffffea0005ffff00 R15: fffffffffffffffe
FS: 00007f9f9a161740(0000) GS:ffff8894971fd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffea0006000008 CR3: 000000017c2ae000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
truncate_inode_pages_range+0x226/0x720
truncate_pagecache+0x57/0x90
...
Fix this issue by skipping the split if truncation aligns with the folio
size, make sure the split page number lies within the folio.
Link: https://lkml.kernel.org/r/20250512062825.3533342-1-yi.zhang@huaweicloud.com
Fixes: 7460b470a1 ("mm/truncate: use folio_split() in truncate operation")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: ErKun Yang <yangerkun@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.