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Lorenzo Stoakes 1f4b030e08 mm/vma: reset VMA iterator on commit_merge() OOM failure
commit 0cf4b1687a upstream.

While an OOM failure in commit_merge() isn't really feasible due to the
allocation which might fail (a maple tree pre-allocation) being 'too small
to fail', we do need to handle this case correctly regardless.

In vma_merge_existing_range(), we can theoretically encounter failures
which result in an OOM error in two ways - firstly dup_anon_vma() might
fail with an OOM error, and secondly commit_merge() failing, ultimately,
to pre-allocate a maple tree node.

The abort logic for dup_anon_vma() resets the VMA iterator to the initial
range, ensuring that any logic looping on this iterator will correctly
proceed to the next VMA.

However the commit_merge() abort logic does not do the same thing.  This
resulted in a syzbot report occurring because mlockall() iterates through
VMAs, is tolerant of errors, but ended up with an incorrect previous VMA
being specified due to incorrect iterator state.

While making this change, it became apparent we are duplicating logic -
the logic introduced in commit 41e6ddcaa0 ("mm/vma: add give_up_on_oom
option on modify/merge, use in uffd release") duplicates the
vmg->give_up_on_oom check in both abort branches.

Additionally, we observe that we can perform the anon_dup check safely on
dup_anon_vma() failure, as this will not be modified should this call
fail.

Finally, we need to reset the iterator in both cases, so now we can simply
use the exact same code to abort for both.

We remove the VM_WARN_ON(err != -ENOMEM) as it would be silly for this to
be otherwise and it allows us to implement the abort check more neatly.

Link: https://lkml.kernel.org/r/20250606125032.164249-1-lorenzo.stoakes@oracle.com
Fixes: 47b16d0462 ("mm: abort vma_modify() on merge out of memory failure")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: syzbot+d16409ea9ecc16ed261a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/6842cc67.a00a0220.29ac89.003b.GAE@google.com/
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-07-06 11:01:48 +02:00
arch x86/pkeys: Simplify PKRU update in signal frame 2025-07-06 11:01:47 +02:00
block block: Clear BIO_EMULATES_ZONE_APPEND flag on BIO completion 2025-06-27 11:11:19 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Redo lookup on EEXIST 2025-06-19 15:31:30 +02:00
Documentation dt-bindings: serial: 8250: Make clocks and clock-frequency exclusive 2025-07-06 11:01:43 +02:00
drivers net: libwx: fix Tx L4 checksum 2025-07-06 11:01:47 +02:00
fs f2fs: fix to zero post-eof page 2025-07-06 11:01:44 +02:00
include vsock/uapi: fix linux/vm_sockets.h userspace compilation errors 2025-07-06 11:01:40 +02:00
init rust: clean Rust 1.88.0's unnecessary_transmutes lint 2025-05-18 08:24:51 +02:00
io_uring io_uring/kbuf: flag partial buffer mappings 2025-07-06 11:01:48 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel perf/core: Fix WARN in perf_cgroup_switch() 2025-06-27 11:11:45 +01:00
lib maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate() 2025-07-06 11:01:43 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/vma: reset VMA iterator on commit_merge() OOM failure 2025-07-06 11:01:48 +02:00
net Bluetooth: L2CAP: Fix L2CAP MTU negotiation 2025-07-06 11:01:43 +02:00
rust rust: arm: fix unknown (to Clang) argument '-mno-fdpic' 2025-07-06 11:01:33 +02:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-05-29 11:02:01 +02:00
scripts rust: compile libcore with edition 2024 for 1.87+ 2025-06-27 11:11:40 +01:00
security selinux: fix selinux_xfrm_alloc_user() to set correct ctx_len 2025-06-27 11:11:38 +01:00
sound ALSA: hda/realtek: Fix built-in mic on ASUS VivoBook X507UAR 2025-07-06 11:01:41 +02:00
tools libbpf: Fix possible use-after-free for externs 2025-07-06 11:01:40 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Add member to struct kvm_gfn_range to indicate private/shared 2025-05-22 14:29:36 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-18 08:24:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.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: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
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 MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.35 2025-06-27 11:11:46 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.