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Ritesh Harjani b45f189a19 ext4: fix accessing uninit percpu counter variable with fast_commit
When running generic/527 with fast_commit configuration, the following
issue is seen on Power.  With fast_commit, during ext4_fc_replay()
(which can be called from ext4_fill_super()), if inode eviction
happens then it can access an uninitialized percpu counter variable.

This patch adds the check before accessing the counters in
ext4_free_inode() path.

[  321.165371] run fstests generic/527 at 2021-04-29 08:38:43
[  323.027786] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: block_validity. Quota mode: none.
[  323.618772] BUG: Unable to handle kernel data access on read at 0x1fbd80000
[  323.619767] Faulting instruction address: 0xc000000000bae78c
cpu 0x1: Vector: 300 (Data Access) at [c000000010706ef0]
    pc: c000000000bae78c: percpu_counter_add_batch+0x3c/0x100
    lr: c0000000006d0bb0: ext4_free_inode+0x780/0xb90
    pid   = 5593, comm = mount
	ext4_free_inode+0x780/0xb90
	ext4_evict_inode+0xa8c/0xc60
	evict+0xfc/0x1e0
	ext4_fc_replay+0xc50/0x20f0
	do_one_pass+0xfe0/0x1350
	jbd2_journal_recover+0x184/0x2e0
	jbd2_journal_load+0x1c0/0x4a0
	ext4_fill_super+0x2458/0x4200
	mount_bdev+0x1dc/0x290
	ext4_mount+0x28/0x40
	legacy_get_tree+0x4c/0xa0
	vfs_get_tree+0x4c/0x120
	path_mount+0xcf8/0xd70
	do_mount+0x80/0xd0
	sys_mount+0x3fc/0x490
	system_call_exception+0x384/0x3d0
	system_call_common+0xec/0x278

Cc: stable@kernel.org
Fixes: 8016e29f43 ("ext4: fast commit recovery path")
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/6cceb9a75c54bef8fa9696c1b08c8df5ff6169e2.1619692410.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-06-02 21:40:42 -04:00
arch Boundary condition fixes for bugs unearthed by the perf fuzzer. 2021-03-21 11:26:21 -07:00
block block: Discard page cache of zone reset target range 2021-03-11 11:49:25 -07:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-08 11:52:17 +01:00
Documentation ext4: handle casefolding with encryption 2021-04-05 22:04:20 -04:00
drivers Staging/IIO driver fixes for 5.12-rc4 2021-03-21 11:54:04 -07:00
fs ext4: fix accessing uninit percpu counter variable with fast_commit 2021-06-02 21:40:42 -04:00
include jbd2: avoid -Wempty-body warnings 2021-04-05 22:39:38 -04:00
init Merge branch 'akpm' (patches from Andrew) 2021-03-14 12:23:34 -07:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel io_uring-5.12-2021-03-21 2021-03-21 12:25:54 -07:00
lib kasan: fix KASAN_STACK dependency for HW_TAGS 2021-03-13 11:27:31 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2021-03-14 12:23:34 -07:00
net module: remove never implemented MODULE_SUPPORTED_DEVICE 2021-03-17 13:16:18 -07:00
samples Merge git://git.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2021-03-09 17:15:56 -08:00
scripts kbuild: fix ld-version.sh to not be affected by locale 2021-03-13 11:12:13 +09:00
security Revert 95ebabde38 ("capabilities: Don't allow writing ambiguous v3 file capabilities") 2021-03-12 15:27:14 -06:00
sound sound fixes for 5.12-rc4 2021-03-19 09:53:32 -07:00
tools selftests: kvm: add set_boot_cpu_id test 2021-03-18 13:55:14 -04:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: move the staging subsystem to lists.linux.dev 2021-03-16 12:17:26 +01:00
Makefile Linux 5.12-rc4 2021-03-21 14:56:43 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text 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.