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Matthew Wilcox (Oracle) 1ac49c8fd4 XArray: Fix xas_create_range() when multi-order entry present
commit 3e3c658055 upstream.

If there is already an entry present that is of order >= XA_CHUNK_SHIFT
when we call xas_create_range(), xas_create_range() will misinterpret
that entry as a node and dereference xa_node->parent, generally leading
to a crash that looks something like this:

general protection fault, probably for non-canonical address 0xdffffc0000000001:
0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 32 Comm: khugepaged Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0
RIP: 0010:xa_parent_locked include/linux/xarray.h:1207 [inline]
RIP: 0010:xas_create_range+0x2d9/0x6e0 lib/xarray.c:725

It's deterministically reproducable once you know what the problem is,
but producing it in a live kernel requires khugepaged to hit a race.
While the problem has been present since xas_create_range() was
introduced, I'm not aware of a way to hit it before the page cache was
converted to use multi-index entries.

Fixes: 6b24ca4a1a ("mm: Use multi-index entries in the page cache")
Reported-by: syzbot+0d2b0bf32ca5cfd09f2e@syzkaller.appspotmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08 14:40:40 +02:00
arch KVM: SVM: fix panic on out-of-bounds guest IRQ 2022-04-08 14:40:39 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-08 14:40:32 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:50:29 +02:00
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-08 14:39:59 +02:00
Documentation ALSA: hda/realtek: Add alc256-samsung-headphone fixup 2022-04-08 14:40:36 +02:00
drivers wireguard: socket: ignore v6 endpoints when ipv6 is disabled 2022-04-08 14:40:40 +02:00
fs ubifs: rename_whiteout: correct old_dir size computing 2022-04-08 14:40:39 +02:00
include serial: 8250: fix XOFF/XON sending when DMA is used 2022-04-08 14:40:28 +02:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-01-05 12:40:34 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:19:10 +01:00
kernel locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-04-08 14:40:32 +02:00
lib XArray: Fix xas_create_range() when multi-order entry present 2022-04-08 14:40:40 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/kmemleak: reset tag when compare object pointer 2022-04-08 14:39:54 +02:00
net net/x25: Fix null-ptr-deref caused by x25_disconnect 2022-04-08 14:40:30 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 14:40:21 +02:00
scripts gcc-plugins/stackleak: Exactly match strings instead of prefixes 2022-04-08 14:40:30 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 14:40:31 +02:00
sound ASoC: SOF: Intel: Fix NULL ptr dereference when ENOMEM 2022-04-08 14:40:39 +02:00
tools selftests: test_vxlan_under_vrf: Fix broken test case 2022-04-08 14:40:29 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-08 14:40:38 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.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 kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
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: adjust GCC PLUGINS after gcc-plugin.sh removal 2021-12-14 11:32:46 +01:00
Makefile Linux 5.10.109 2022-03-28 09:57:11 +02:00
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.