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Sungjong Seo e705b16800 exfat: release s_lock before calling dir_emit()
commit ff84772fd4 upstream.

There is a potential deadlock reported by syzbot as below:

======================================================
WARNING: possible circular locking dependency detected
6.4.0-next-20230707-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor330/5073 is trying to acquire lock:
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:151 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5293 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x369/0x510 mm/memory.c:5344
but task is already holding lock:
ffff888019f760e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x117/0xb50 fs/exfat/dir.c:232

which lock already depends on the new lock.

Chain exists of:
  &mm->mmap_lock --> mapping.invalidate_lock#3 --> &sbi->s_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_lock);
                               lock(mapping.invalidate_lock#3);
                               lock(&sbi->s_lock);
  rlock(&mm->mmap_lock);

Let's try to avoid above potential deadlock condition by moving dir_emit*()
out of sbi->s_lock coverage.

Fixes: ca06197382 ("exfat: add directory operations")
Cc: stable@vger.kernel.org #v5.7+
Reported-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/00000000000078ee7e060066270b@google.com/T/#u
Tested-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 12:14:20 +02:00
Documentation Documentation: kdump: Add va_kernel_pa_offset for RISCV64 2023-08-11 12:14:19 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch KVM: s390: fix sthyi error handling 2023-08-11 12:14:08 +02:00
block blk-mq: Fix stall due to recursive flush plug 2023-08-03 10:25:41 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
drivers firmware: arm_scmi: Drop OF node reference in the transport channel setup 2023-08-11 12:14:19 +02:00
fs exfat: release s_lock before calling dir_emit() 2023-08-11 12:14:20 +02:00
include vxlan: Fix nexthop hash size 2023-08-11 12:14:17 +02:00
init init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init() 2023-08-08 20:04:49 +02:00
io_uring io_uring: gate iowait schedule on having pending requests 2023-08-03 10:26:10 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel bpf, cpumap: Handle skb as well when clean up ptr_ring 2023-08-11 12:14:15 +02:00
lib lib/bitmap: workaround const_eval test build failure 2023-08-11 12:14:07 +02:00
mm mm: lock_vma_under_rcu() must check vma->anon_vma under vma lock 2023-08-11 12:14:05 +02:00
net libceph: fix potential hang in ceph_osdc_notify() 2023-08-11 12:14:19 +02:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:14:18 +02:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:54:09 +02:00
scripts kbuild: rust: avoid creating temporary files 2023-07-27 08:57:06 +02:00
security security: keys: Modify mismatched function name 2023-07-27 08:56:59 +02:00
sound ASoC: wm8904: Fill the cache for WM8904_ADC_TEST_0 register 2023-08-03 10:26:12 +02:00
tools test/vsock: remove vsock_perf executable on `make clean` 2023-08-11 12:14:18 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:26:01 +02:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.9 2023-08-08 20:04:53 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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.