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Jiachen Zhang 35ef2ee74d ovl: drop WARN_ON() dentry is NULL in ovl_encode_fh()
commit dd524b7f31 upstream.

Some code paths cannot guarantee the inode have any dentry alias. So
WARN_ON() all !dentry may flood the kernel logs.

For example, when an overlayfs inode is watched by inotifywait (1), and
someone is trying to read the /proc/$(pidof inotifywait)/fdinfo/INOTIFY_FD,
at that time if the dentry has been reclaimed by kernel (such as
echo 2 > /proc/sys/vm/drop_caches), there will be a WARN_ON(). The
printed call stack would be like:

    ? show_mark_fhandle+0xf0/0xf0
    show_mark_fhandle+0x4a/0xf0
    ? show_mark_fhandle+0xf0/0xf0
    ? seq_vprintf+0x30/0x50
    ? seq_printf+0x53/0x70
    ? show_mark_fhandle+0xf0/0xf0
    inotify_fdinfo+0x70/0x90
    show_fdinfo.isra.4+0x53/0x70
    seq_show+0x130/0x170
    seq_read+0x153/0x440
    vfs_read+0x94/0x150
    ksys_read+0x5f/0xe0
    do_syscall_64+0x59/0x1e0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

So let's drop WARN_ON() to avoid kernel log flooding.

Reported-by: Hongbo Yin <yinhongbo@bytedance.com>
Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Signed-off-by: Tianci Zhang <zhangtianci.1997@bytedance.com>
Fixes: 8ed5eec9d6 ("ovl: encode pure upper file handles")
Cc: <stable@vger.kernel.org> # v4.16
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-17 14:22:51 +02:00
arch riscv: set default pm_power_off to NULL 2022-08-17 14:22:49 +02:00
block block: fix default IO priority handling again 2022-08-11 13:07:50 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: memneq - move into lib/ 2022-06-22 14:22:03 +02:00
Documentation x86/speculation: Add RSB VM Exit protections 2022-08-11 13:07:54 +02:00
drivers crypto: ccp - Use kzalloc for sev ioctl interfaces to prevent kernel memory leak 2022-08-17 14:22:51 +02:00
fs ovl: drop WARN_ON() dentry is NULL in ovl_encode_fh() 2022-08-17 14:22:51 +02:00
include fix short copy handling in copy_mc_pipe_to_iter() 2022-08-17 14:22:51 +02:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2022-06-09 10:23:26 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:23:10 +02:00
kernel locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter 2022-08-03 12:03:56 +02:00
lib fix short copy handling in copy_mc_pipe_to_iter() 2022-08-17 14:22:51 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm page_alloc: fix invalid watermark check on a negative value 2022-08-03 12:03:55 +02:00
net sctp: leave the err path free in sctp_stream_init to sctp_stream_free 2022-08-03 12:03:54 +02:00
samples samples/landlock: Format with clang-format 2022-06-09 10:23:23 +02:00
scripts x86/extable: Rework the exception table mechanics 2022-07-29 17:25:25 +02:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-29 17:25:05 +02:00
sound ALSA: hda/realtek: Add a quirk for HP OMEN 15 (8786) mute LED 2022-08-17 14:22:50 +02:00
tools x86/speculation: Add RSB VM Exit protections 2022-08-11 13:07:54 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Don't null dereference ops->destroy 2022-07-29 17:25:24 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 Input: goodix - add a goodix.h header file 2022-07-12 16:34:51 +02:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-17 14:22:44 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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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 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.