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Filename Latest commit message Latest commit date
Miklos Szeredi c4461ca7a8 ovl: fix deadlock in splice write
commit 9b91b6b019fda817eb52f728eb9c79b3579760bc upstream.

There's possibility of an ABBA deadlock in case of a splice write to an
overlayfs file and a concurrent splice write to a corresponding real file.

The call chain for splice to an overlay file:

 -> do_splice                     [takes sb_writers on overlay file]
   -> do_splice_from
     -> iter_file_splice_write    [takes pipe->mutex]
       -> vfs_iter_write
         ...
         -> ovl_write_iter        [takes sb_writers on real file]

And the call chain for splice to a real file:

 -> do_splice                     [takes sb_writers on real file]
   -> do_splice_from
     -> iter_file_splice_write    [takes pipe->mutex]

Syzbot successfully bisected this to commit 82a763e61e2b ("ovl: simplify
file splice").

Fix by reverting the write part of the above commit and by adding missing
bits from ovl_write_iter() into ovl_splice_write().

Fixes: 82a763e61e2b ("ovl: simplify file splice")
Reported-and-tested-by: syzbot+579885d1a9a833336209@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-17 09:48:49 +01:00
arch parisc: Fix set_fixmap() on PA1.x CPUs 2021-11-17 09:48:49 +01:00
block block: remove inaccurate requeue check 2021-11-17 09:48:31 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation xen/balloon: add late_initcall_sync() for initial ballooning done 2021-11-17 09:48:25 +01:00
drivers irqchip/sifive-plic: Fixup EOI failed when masked 2021-11-17 09:48:49 +01:00
fs ovl: fix deadlock in splice write 2021-11-17 09:48:49 +01:00
include net, neigh: Enable state migration between NUD_PERMANENT and NTF_USE 2021-11-17 09:48:49 +01:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel PM: hibernate: fix sparse warnings 2021-11-17 09:48:39 +01:00
lib lib/xz: Validate the value before assigning it to an enum variable 2021-11-17 09:48:31 +01:00
LICENSES
mm mm/zsmalloc.c: close race window between zs_pool_dec_isolated() and zs_unregister_migration() 2021-11-17 09:48:47 +01:00
net 9p/net: fix missing error check in p9_check_errors 2021-11-17 09:48:49 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts leaking_addresses: Always print a trailing newline 2021-11-17 09:48:31 +01:00
security apparmor: fix error check 2021-11-17 09:48:44 +01:00
sound ASoC: cs42l42: Defer probe if request_threaded_irq() returns EPROBE_DEFER 2021-11-17 09:48:43 +01:00
tools selftests/net: udpgso_bench_rx: fix port argument 2021-11-17 09:48:48 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.159 2021-11-12 14:43:05 +01:00
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.