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John Hubbard 69d319450d mm/gup: handle NULL pages in unpin_user_pages()
commit a1268be280 upstream.

The recent addition of "pofs" (pages or folios) handling to gup has a
flaw: it assumes that unpin_user_pages() handles NULL pages in the pages**
array.  That's not the case, as I discovered when I ran on a new
configuration on my test machine.

Fix this by skipping NULL pages in unpin_user_pages(), just like
unpin_folios() already does.

Details: when booting on x86 with "numa=fake=2 movablecore=4G" on Linux
6.12, and running this:

    tools/testing/selftests/mm/gup_longterm

...I get the following crash:

BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:sanity_check_pinned_pages+0x3a/0x2d0
...
Call Trace:
 <TASK>
 ? __die_body+0x66/0xb0
 ? page_fault_oops+0x30c/0x3b0
 ? do_user_addr_fault+0x6c3/0x720
 ? irqentry_enter+0x34/0x60
 ? exc_page_fault+0x68/0x100
 ? asm_exc_page_fault+0x22/0x30
 ? sanity_check_pinned_pages+0x3a/0x2d0
 unpin_user_pages+0x24/0xe0
 check_and_migrate_movable_pages_or_folios+0x455/0x4b0
 __gup_longterm_locked+0x3bf/0x820
 ? mmap_read_lock_killable+0x12/0x50
 ? __pfx_mmap_read_lock_killable+0x10/0x10
 pin_user_pages+0x66/0xa0
 gup_test_ioctl+0x358/0xb20
 __se_sys_ioctl+0x6b/0xc0
 do_syscall_64+0x7b/0x150
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Link: https://lkml.kernel.org/r/20241121034933.77502-1-jhubbard@nvidia.com
Fixes: 94efde1d15 ("mm/gup: avoid an unnecessary allocation call for FOLL_LONGTERM cases")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-12-14 20:03:32 +01:00
arch x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation 2024-12-14 20:03:31 +01:00
block block: don't verify IO lock for freeze/unfreeze in elevator_init_mq() 2024-12-05 14:03:10 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-05 14:01:18 +01:00
Documentation dt-bindings: net: fec: add pps channel property 2024-12-09 10:41:11 +01:00
drivers mmc: core: Further prevent card detect during shutdown 2024-12-14 20:03:31 +01:00
fs ocfs2: update seq_file index in ocfs2_dlm_seq_next 2024-12-14 20:03:31 +01:00
include stackdepot: fix stack_depot_save_flags() in NMI context 2024-12-14 20:03:32 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring: Change res2 parameter type in io_uring_cmd_done 2024-12-14 20:03:26 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel sched/numa: fix memory leak due to the overwritten vma->numab_state 2024-12-14 20:03:32 +01:00
lib lib: stackinit: hide never-taken branch from compiler 2024-12-14 20:03:32 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/gup: handle NULL pages in unpin_user_pages() 2024-12-14 20:03:32 +01:00
net xsk: fix OOB map writes when deleting elements 2024-12-14 20:03:31 +01:00
rust rust: block: fix formatting of kernel::block::mq::request module 2024-12-05 14:02:21 +01:00
samples kfifo: don't include dma-mapping.h in kfifo.h 2024-12-05 14:03:03 +01:00
scripts modpost: Add .irqentry.text to OTHER_SECTIONS 2024-12-14 20:03:30 +01:00
security apparmor: test: Fix memory leak for aa_unpack_strdup() 2024-12-05 14:02:46 +01:00
sound ALSA: hda/realtek: Add support for Samsung Galaxy Book3 360 (NP730QFG) 2024-12-14 20:03:23 +01:00
tools selftest: hugetlb_dio: fix test naming 2024-12-14 20:03:27 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +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 Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.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 location of media main tree 2024-12-05 14:02:42 +01:00
Makefile rust: allow clippy::needless_lifetimes 2024-12-14 20:03:20 +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.