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Linus Torvalds a95a24fcae mm: avoid leaving partial pfn mappings around in error case
commit 79a61cc3fc upstream.

As Jann points out, PFN mappings are special, because unlike normal
memory mappings, there is no lifetime information associated with the
mapping - it is just a raw mapping of PFNs with no reference counting of
a 'struct page'.

That's all very much intentional, but it does mean that it's easy to
mess up the cleanup in case of errors.  Yes, a failed mmap() will always
eventually clean up any partial mappings, but without any explicit
lifetime in the page table mapping itself, it's very easy to do the
error handling in the wrong order.

In particular, it's easy to mistakenly free the physical backing store
before the page tables are actually cleaned up and (temporarily) have
stale dangling PTE entries.

To make this situation less error-prone, just make sure that any partial
pfn mapping is torn down early, before any other error handling.

Reported-and-tested-by: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-09-18 19:24:07 +02:00
arch x86/hyperv: fix kexec crash due to VP assist page corruption 2024-09-18 19:24:07 +02:00
block block: remove the blk_flush_integrity call in blk_integrity_unregister 2024-09-08 07:54:47 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: aead,cipher - zeroize key buffer after use 2024-07-11 12:49:04 +02:00
Documentation hwspinlock: Introduce hwspin_lock_bust() 2024-09-08 07:54:43 +02:00
drivers dm-integrity: fix a race condition when accessing recalc_sector 2024-09-18 19:24:07 +02:00
fs NFS: Avoid unnecessary rescanning of the per-server delegation list 2024-09-18 19:24:06 +02:00
include net: tighten bad gso csum offset check in virtio_net_hdr 2024-09-18 19:24:07 +02:00
init rust: fix the default format for CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT 2024-08-29 17:33:29 +02:00
io_uring io_uring: fix io_match_task must_hold 2024-08-03 08:54:41 +02:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
lib lib/generic-radix-tree.c: Fix rare race in __genradix_ptr_alloc() 2024-09-12 11:11:39 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: avoid leaving partial pfn mappings around in error case 2024-09-18 19:24:07 +02:00
net mptcp: pm: Fix uaf in __timer_delete_sync 2024-09-18 19:24:06 +02:00
rust rust: kbuild: fix export of bss symbols 2024-09-12 11:11:32 +02:00
samples bpf: Replace bpf_lpm_trie_key 0-length array with flexible array 2024-08-19 06:04:27 +02:00
scripts scripts: kconfig: merge_config: config files: add a trailing newline 2024-09-18 19:24:05 +02:00
security smack: unix sockets: fix accept()ed socket label 2024-09-12 11:11:29 +02:00
sound ASoC: sunxi: sun4i-i2s: fix LRCLK polarity in i2s mode 2024-09-12 11:11:44 +02:00
tools selftests: mptcp: join: restrict fullmesh endp on 1st sf 2024-09-18 19:24:06 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:49:11 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.51 2024-09-12 11:11:45 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 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.