When a page fault occurs in a secret memory file created with
`memfd_secret(2)`, the kernel will allocate a new folio for it, mark the
underlying page as not-present in the direct map, and add it to the file
mapping.
If two tasks cause a fault in the same page concurrently, both could end
up allocating a folio and removing the page from the direct map, but only
one would succeed in adding the folio to the file mapping. The task that
failed undoes the effects of its attempt by (a) freeing the folio again
and (b) putting the page back into the direct map. However, by doing
these two operations in this order, the page becomes available to the
allocator again before it is placed back in the direct mapping.
If another task attempts to allocate the page between (a) and (b), and the
kernel tries to access it via the direct map, it would result in a
supervisor not-present page fault.
Fix the ordering to restore the direct map before the folio is freed.
Link: https://lkml.kernel.org/r/20251031120955.92116-1-lance.yang@linux.dev
Fixes: 1507f51255 ("mm: introduce memfd_secret system call to create "secret" memory areas")
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Reported-by: Google Big Sleep <big-sleep-vuln-reports@google.com>
Closes: https://lore.kernel.org/linux-mm/CAEXGt5QeDpiHTu3K9tvjUTPqo+d-=wuCNYPa+6sWKrdQJ-ATdg@mail.gmail.com/
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On arm64 with MTE enabled, a page mapped as Normal Tagged (PROT_MTE) in
user space will need to have its allocation tags initialised. This is
normally done in the arm64 set_pte_at() after checking the memory
attributes. Such page is also marked with the PG_mte_tagged flag to avoid
subsequent clearing. Since this relies on having a struct page,
pte_special() mappings are ignored.
Commit d82d09e482 ("mm/huge_memory: mark PMD mappings of the huge zero
folio special") maps the huge zero folio special and the arm64
set_pmd_at() will no longer zero the tags. There is no guarantee that the
tags are zero, especially if parts of this huge page have been previously
tagged.
It's fairly easy to detect this by regularly dropping the caches to
force the reallocation of the huge zero folio.
Allocate the huge zero folio with the __GFP_ZEROTAGS flag. In addition,
do not warn in the arm64 __access_remote_tags() when reading tags from the
huge zero page.
I bundled the arm64 change in here as well since they are both related to
the commit mapping the huge zero folio as special.
[catalin.marinas@arm.com: handle arch mte_zero_clear_page_tags() code issuing MTE instructions]
Link: https://lkml.kernel.org/r/aQi8dA_QpXM8XqrE@arm.com
Link: https://lkml.kernel.org/r/20251031170133.280742-1-catalin.marinas@arm.com
Fixes: d82d09e482 ("mm/huge_memory: mark PMD mappings of the huge zero folio special")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Tested-by: Beleswar Padhi <b-padhi@ti.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Aishwarya TCV <aishwarya.tcv@arm.com>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Because kthread_stop did not stop sc_task properly and returned -EINTR,
the sc_timer was not properly closed, ultimately causing the problem [1]
reported by syzbot when freeing sci due to the sc_timer not being closed.
Because the thread sc_task main function nilfs_segctor_thread() returns 0
when it succeeds, when the return value of kthread_stop() is not 0 in
nilfs_segctor_destroy(), we believe that it has not properly closed
sc_timer.
We use timer_shutdown_sync() to sync wait for sc_timer to shutdown, and
set the value of sc_task to NULL under the protection of lock
sc_state_lock, so as to avoid the issue caused by sc_timer not being
properly shutdowned.
[1]
ODEBUG: free active (active state 0) object: 00000000dacb411a object type: timer_list hint: nilfs_construction_timeout
Call trace:
nilfs_segctor_destroy fs/nilfs2/segment.c:2811 [inline]
nilfs_detach_log_writer+0x668/0x8cc fs/nilfs2/segment.c:2877
nilfs_put_super+0x4c/0x12c fs/nilfs2/super.c:509
Link: https://lkml.kernel.org/r/20251029225226.16044-1-konishi.ryusuke@gmail.com
Fixes: 3f66cc261c ("nilfs2: use kthread_create and kthread_stop for the log writer thread")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+24d8b70f039151f65590@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=24d8b70f039151f65590
Tested-by: syzbot+24d8b70f039151f65590@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Cc: <stable@vger.kernel.org> [6.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Support for parsing PC source info in stacktraces (e.g. '(P)') was added
in commit 2bff77c665 ("scripts/decode_stacktrace.sh: fix decoding of
lines with an additional info"). However, this logic was placed after the
build ID processing. This incorrect order fails to parse lines containing
both elements, e.g.:
drm_gem_mmap_obj+0x114/0x200 [drm 03d0564e0529947d67bb2008c3548be77279fd27] (P)
This patch fixes the problem by extracting the PC source info first and
then processing the module build ID. With this change, the line above is
now properly parsed as such:
drm_gem_mmap_obj (./include/linux/mmap_lock.h:212 ./include/linux/mm.h:811 drivers/gpu/drm/drm_gem.c:1177) drm (P)
While here, also add a brief explanation the build ID section.
Link: https://lkml.kernel.org/r/20251030010347.2731925-1-cmllamas@google.com
Fixes: 2bff77c665 ("scripts/decode_stacktrace.sh: fix decoding of lines with an additional info")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthieu Baerts <matttbe@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Puranjay Mohan <puranjay@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In DAMON's damon_sysfs_repeat_call_fn(), time_before() is used to compare
the current jiffies with next_update_jiffies to determine whether to
update the sysfs files at this moment.
On 32-bit systems, the kernel initializes jiffies to "-5 minutes" to make
jiffies wrap bugs appear earlier. However, this causes time_before() in
damon_sysfs_repeat_call_fn() to unexpectedly return true during the first
5 minutes after boot on 32-bit systems (see [1] for more explanation,
which fixes another jiffies-related issue before). As a result, DAMON
does not update sysfs files during that period.
There is also an issue unrelated to the system's word size[2]: if the
user stops DAMON just after next_update_jiffies is updated and restarts
it after 'refresh_ms' or a longer delay, next_update_jiffies will retain
an older value, causing time_before() to return false and the update to
happen earlier than expected.
Fix these issues by making next_update_jiffies a global variable and
initializing it each time DAMON is started.
Link: https://lkml.kernel.org/r/20251030020746.967174-3-yanquanmin1@huawei.com
Link: https://lkml.kernel.org/r/20250822025057.1740854-1-ekffu200098@gmail.com [1]
Link: https://lore.kernel.org/all/20251029013038.66625-1-sj@kernel.org/ [2]
Fixes: d809a7c64b ("mm/damon/sysfs: implement refresh_ms file internal work")
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: fixes for the jiffies-related issues", v2.
On 32-bit systems, the kernel initializes jiffies to "-5 minutes" to make
jiffies wrap bugs appear earlier. However, this may cause the
time_before() series of functions to return unexpected values, resulting
in DAMON not functioning as intended. Meanwhile, similar issues exist in
some specific user operation scenarios.
This patchset addresses these issues. The first patch is about the
DAMON_STAT module, and the second patch is about the core layer's sysfs.
This patch (of 2):
In DAMON_STAT's damon_stat_damon_call_fn(), time_before_eq() is used to
avoid unnecessarily frequent stat update.
On 32-bit systems, the kernel initializes jiffies to "-5 minutes" to make
jiffies wrap bugs appear earlier. However, this causes time_before_eq()
in DAMON_STAT to unexpectedly return true during the first 5 minutes after
boot on 32-bit systems (see [1] for more explanation, which fixes another
jiffies-related issue before). As a result, DAMON_STAT does not update
any monitoring results during that period, which becomes more confusing
when DAMON_STAT_ENABLED_DEFAULT is enabled.
There is also an issue unrelated to the system's word size[2]: if the user
stops DAMON_STAT just after last_refresh_jiffies is updated and restarts
it after 5 seconds or a longer delay, last_refresh_jiffies will retain an
older value, causing time_before_eq() to return false and the update to
happen earlier than expected.
Fix these issues by making last_refresh_jiffies a global variable and
initializing it each time DAMON_STAT is started.
Link: https://lkml.kernel.org/r/20251030020746.967174-2-yanquanmin1@huawei.com
Link: https://lkml.kernel.org/r/20250822025057.1740854-1-ekffu200098@gmail.com [1]
Link: https://lore.kernel.org/all/20251028143250.50144-1-sj@kernel.org/ [2]
Fixes: fabdd1e911 ("mm/damon/stat: calculate and expose estimated memory bandwidth")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
maple_tree tracepoints contain pointers to function names. Such a pointer
is saved when a tracepoint logs an event. There's no guarantee that it's
still valid when the event is parsed later and the pointer is dereferenced.
The kernel warns about these unsafe pointers.
event 'ma_read' has unsafe pointer field 'fn'
WARNING: kernel/trace/trace.c:3779 at ignore_event+0x1da/0x1e4
Mark the function names as tracepoint_string() to fix the events.
One case that doesn't work without my patch would be trace-cmd record
to save the binary ringbuffer and trace-cmd report to parse it in
userspace. The address of __func__ can't be dereferenced from
userspace but tracepoint_string will add an entry to
/sys/kernel/tracing/printk_formats
Link: https://lkml.kernel.org/r/20251030155537.87972-1-martin@kaiser.cx
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When emitting the order of the allocation for a hash table,
alloc_large_system_hash() unconditionally subtracts PAGE_SHIFT from log
base 2 of the allocation size. This is not correct if the allocation size
is smaller than a page, and yields a negative value for the order as seen
below:
TCP established hash table entries: 32 (order: -4, 256 bytes, linear) TCP
bind hash table entries: 32 (order: -2, 1024 bytes, linear)
Use get_order() to compute the order when emitting the hash table
information to correctly handle cases where the allocation size is smaller
than a page:
TCP established hash table entries: 32 (order: 0, 256 bytes, linear) TCP
bind hash table entries: 32 (order: 0, 1024 bytes, linear)
Link: https://lkml.kernel.org/r/20251028191020.413002-1-isaacmanjarres@google.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fix SIGBUS semantics with large folios", v3.
Accessing memory within a VMA, but beyond i_size rounded up to the next
page size, is supposed to generate SIGBUS.
Darrick reported[1] an xfstests regression in v6.18-rc1. generic/749
failed due to missing SIGBUS. This was caused by my recent changes that
try to fault in the whole folio where possible:
19773df031 ("mm/fault: try to map the entire file folio in finish_fault()")
357b92761d ("mm/filemap: map entire large folio faultaround")
These changes did not consider i_size when setting up PTEs, leading to
xfstest breakage.
However, the problem has been present in the kernel for a long time -
since huge tmpfs was introduced in 2016. The kernel happily maps
PMD-sized folios as PMD without checking i_size. And huge=always tmpfs
allocates PMD-size folios on any writes.
I considered this corner case when I implemented a large tmpfs, and my
conclusion was that no one in their right mind should rely on receiving a
SIGBUS signal when accessing beyond i_size. I cannot imagine how it could
be useful for the workload.
But apparently filesystem folks care a lot about preserving strict SIGBUS
semantics.
Generic/749 was introduced last year with reference to POSIX, but no real
workloads were mentioned. It also acknowledged the tmpfs deviation from
the test case.
POSIX indeed says[3]:
References within the address range starting at pa and
continuing for len bytes to whole pages following the end of an
object shall result in delivery of a SIGBUS signal.
The patchset fixes the regression introduced by recent changes as well as
more subtle SIGBUS breakage due to split failure on truncation.
This patch (of 2):
Accesses within VMA, but beyond i_size rounded up to PAGE_SIZE are
supposed to generate SIGBUS.
Recent changes attempted to fault in full folio where possible. They did
not respect i_size, which led to populating PTEs beyond i_size and
breaking SIGBUS semantics.
Darrick reported generic/749 breakage because of this.
However, the problem existed before the recent changes. With huge=always
tmpfs, any write to a file leads to PMD-size allocation. Following the
fault-in of the folio will install PMD mapping regardless of i_size.
Fix filemap_map_pages() and finish_fault() to not install:
- PTEs beyond i_size;
- PMD mappings across i_size;
Make an exception for shmem/tmpfs that for long time intentionally
mapped with PMDs across i_size.
Link: https://lkml.kernel.org/r/20251027115636.82382-1-kirill@shutemov.name
Link: https://lkml.kernel.org/r/20251027115636.82382-2-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Fixes: 6795801366 ("xfs: Support large folios")
Reported-by: "Darrick J. Wong" <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pde is erased from subdir rbtree through rb_erase(), but not set the node
to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE()
set the erased node to EMPTY, then pde_subdir_next() will return NULL to
avoid uaf access.
We found an uaf issue while using stress-ng testing, need to run testcase
getdent and tun in the same time. The steps of the issue is as follows:
1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current
pde is tun3;
2) in the [time windows] unregister netdevice tun3 and tun2, and erase
them from rbtree. erase tun3 first, and then erase tun2. the
pde(tun2) will be released to slab;
3) continue to getdent process, then pde_subdir_next() will return
pde(tun2) which is released, it will case uaf access.
CPU 0 | CPU 1
-------------------------------------------------------------------------
traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2
sys_getdents64() |
iterate_dir() |
proc_readdir() |
proc_readdir_de() | snmp6_unregister_dev()
pde_get(de); | proc_remove()
read_unlock(&proc_subdir_lock); | remove_proc_subtree()
| write_lock(&proc_subdir_lock);
[time window] | rb_erase(&root->subdir_node, &parent->subdir);
| write_unlock(&proc_subdir_lock);
read_lock(&proc_subdir_lock); |
next = pde_subdir_next(de); |
pde_put(de); |
de = next; //UAF |
rbtree of dev_snmp6
|
pde(tun3)
/ \
NULL pde(tun2)
Link: https://lkml.kernel.org/r/20251025024233.158363-1-albin_yang@163.com
Signed-off-by: Wei Yang <albinwyang@tencent.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: wangzijie <wangzijie1@honor.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, scan_get_next_rmap_item() walks every page address in a VMA to
locate mergeable pages. This becomes highly inefficient when scanning
large virtual memory areas that contain mostly unmapped regions, causing
ksmd to use large amount of cpu without deduplicating much pages.
This patch replaces the per-address lookup with a range walk using
walk_page_range(). The range walker allows KSM to skip over entire
unmapped holes in a VMA, avoiding unnecessary lookups. This problem was
previously discussed in [1].
Consider the following test program which creates a 32 TiB mapping in the
virtual address space but only populates a single page:
#include <unistd.h>
#include <stdio.h>
#include <sys/mman.h>
/* 32 TiB */
const size_t size = 32ul * 1024 * 1024 * 1024 * 1024;
int main() {
char *area = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_NORESERVE | MAP_PRIVATE | MAP_ANON, -1, 0);
if (area == MAP_FAILED) {
perror("mmap() failed\n");
return -1;
}
/* Populate a single page such that we get an anon_vma. */
*area = 0;
/* Enable KSM. */
madvise(area, size, MADV_MERGEABLE);
pause();
return 0;
}
$ ./ksm-sparse &
$ echo 1 > /sys/kernel/mm/ksm/run
Without this patch ksmd uses 100% of the cpu for a long time (more then 1
hour in my test machine) scanning all the 32 TiB virtual address space
that contain only one mapped page. This makes ksmd essentially deadlocked
not able to deduplicate anything of value. With this patch ksmd walks
only the one mapped page and skips the rest of the 32 TiB virtual address
space, making the scan fast using little cpu.
Link: https://lkml.kernel.org/r/20251023035841.41406-1-pedrodemargomes@gmail.com
Link: https://lkml.kernel.org/r/20251022153059.22763-1-pedrodemargomes@gmail.com
Link: https://lore.kernel.org/linux-mm/423de7a3-1c62-4e72-8e79-19a6413e420c@redhat.com/ [1]
Fixes: 31dbd01f31 ("ksm: Kernel SamePage Merging")
Signed-off-by: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Co-developed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: craftfever <craftfever@airmail.cc>
Closes: https://lkml.kernel.org/r/020cf8de6e773bb78ba7614ef250129f11a63781@murena.io
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KHO allocates metadata for its preserved memory map using the slab
allocator via kzalloc(). This metadata is temporary and is used by the
next kernel during early boot to find preserved memory.
A problem arises when KFENCE is enabled. kzalloc() calls can be randomly
intercepted by kfence_alloc(), which services the allocation from a
dedicated KFENCE memory pool. This pool is allocated early in boot via
memblock.
When booting via KHO, the memblock allocator is restricted to a "scratch
area", forcing the KFENCE pool to be allocated within it. This creates a
conflict, as the scratch area is expected to be ephemeral and
overwriteable by a subsequent kexec. If KHO metadata is placed in this
KFENCE pool, it leads to memory corruption when the next kernel is loaded.
To fix this, modify KHO to allocate its metadata directly from the buddy
allocator instead of slab.
Link: https://lkml.kernel.org/r/20251021000852.2924827-4-pasha.tatashin@soleen.com
Fixes: fc33e4b44b ("kexec: enable KHO support for memory preservation")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: David Matlack <dmatlack@google.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Samiullah Khawaja <skhawaja@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KHO memory preservation metadata is preserved in 512 byte chunks which
requires their allocation from slab allocator. Slabs are not safe to be
used with KHO because of kfence, and because partial slabs may lead leaks
to the next kernel. Change the size to be PAGE_SIZE.
The kfence specifically may cause memory corruption, where it randomly
provides slab objects that can be within the scratch area. The reason for
that is that kfence allocates its objects prior to KHO scratch is marked
as CMA region.
While this change could potentially increase metadata overhead on systems
with sparsely preserved memory, this is being mitigated by ongoing work to
reduce sparseness during preservation via 1G guest pages. Furthermore,
this change aligns with future work on a stateless KHO, which will also
use page-sized bitmaps for its radix tree metadata.
Link: https://lkml.kernel.org/r/20251021000852.2924827-3-pasha.tatashin@soleen.com
Fixes: fc33e4b44b ("kexec: enable KHO support for memory preservation")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Matlack <dmatlack@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Samiullah Khawaja <skhawaja@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "KHO: kfence + KHO memory corruption fix", v3.
This series fixes a memory corruption bug in KHO that occurs when KFENCE
is enabled.
The root cause is that KHO metadata, allocated via kzalloc(), can be
randomly serviced by kfence_alloc(). When a kernel boots via KHO, the
early memblock allocator is restricted to a "scratch area". This forces
the KFENCE pool to be allocated within this scratch area, creating a
conflict. If KHO metadata is subsequently placed in this pool, it gets
corrupted during the next kexec operation.
Google is using KHO and have had obscure crashes due to this memory
corruption, with stacks all over the place. I would prefer this fix to be
properly backported to stable so we can also automatically consume it once
we switch to the upstream KHO.
Patch 1/3 introduces a debug-only feature (CONFIG_KEXEC_HANDOVER_DEBUG)
that adds checks to detect and fail any operation that attempts to place
KHO metadata or preserved memory within the scratch area. This serves as
a validation and diagnostic tool to confirm the problem without affecting
production builds.
Patch 2/3 Increases bitmap to PAGE_SIZE, so buddy allocator can be used.
Patch 3/3 Provides the fix by modifying KHO to allocate its metadata
directly from the buddy allocator instead of slab. This bypasses the
KFENCE interception entirely.
This patch (of 3):
It is invalid for KHO metadata or preserved memory regions to be located
within the KHO scratch area, as this area is overwritten when the next
kernel is loaded, and used early in boot by the next kernel. This can
lead to memory corruption.
Add checks to kho_preserve_* and KHO's internal metadata allocators
(xa_load_or_alloc, new_chunk) to verify that the physical address of the
memory does not overlap with any defined scratch region. If an overlap is
detected, the operation will fail and a WARN_ON is triggered. To avoid
performance overhead in production kernels, these checks are enabled only
when CONFIG_KEXEC_HANDOVER_DEBUG is selected.
[rppt@kernel.org: fix KEXEC_HANDOVER_DEBUG Kconfig dependency]
Link: https://lkml.kernel.org/r/aQHUyyFtiNZhx8jo@kernel.org
[pasha.tatashin@soleen.com: build fix]
Link: https://lkml.kernel.org/r/CA+CK2bBnorfsTymKtv4rKvqGBHs=y=MjEMMRg_tE-RME6n-zUw@mail.gmail.com
Link: https://lkml.kernel.org/r/20251021000852.2924827-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20251021000852.2924827-2-pasha.tatashin@soleen.com
Fixes: fc33e4b44b ("kexec: enable KHO support for memory preservation")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Matlack <dmatlack@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Samiullah Khawaja <skhawaja@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull i2c fix from Wolfram Sang:
"Two reverts merged into one commit to handle a regression caused by a
wrong cleanup because the underlying implications were unclear"
* tag 'i2c-for-6.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: muxes: pca954x: Fix broken reset-gpio usage
Pull Kbuild fixes from Nathan Chancellor:
- Strip trailing padding bytes from modules.builtin.modinfo to fix
error during modules_install with certain versions of kmod
- Drop unused static inline function warning in .c files with clang
from W=1 to W=2
- Ensure kernel-doc.py invocations use the PYTHON3 make variable to
ensure user's choice of Python interpreter is always respected
* tag 'kbuild-fixes-6.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: Let kernel-doc.py use PYTHON3 override
compiler_types: Move unused static inline functions warning to W=2
kbuild: Strip trailing padding bytes from modules.builtin.modinfo
It is possible to force a specific version of python to be used when
building the kernel by passing PYTHON3= on the make command line.
However kernel-doc.py is currently called with python3 hard-coded and
thus ignores this setting.
Use $(PYTHON3) to run $(KERNELDOC) so that the desired version of
python is used.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://patch.msgid.link/20251107192933.2bfe9e57@endymion
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Pull drm fix from Dave Airlie:
"Brown paper bag, the dma mask fix which I applied and actually looked
through for bad things, actually broke newer GPUs, there might be some
latent part in the boot path that is assuming 32-bit still, but we
will figure that out elsewhere.
nouveau:
- revert DMA mask change"
* tag 'drm-fixes-2025-11-09' of https://gitlab.freedesktop.org/drm/kernel:
Revert "drm/nouveau: set DMA mask before creating the flush page"
Pull x86 fixes from Ingo Molnar:
- Fix AMD PCI root device caching regression that triggers
on certain firmware variants
- Fix the zen5_rdseed_microcode[] array to be NULL-terminated
- Add more AMD models to microcode signature checking
* tag 'x86-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode/AMD: Add more known models to entry sign checking
x86/CPU/AMD: Add missing terminator for zen5_rdseed_microcode
x86/amd_node: Fix AMD root device caching
Pull scheduler fix from Ingo Molnar:
"Fix a group-throttling bug in the fair scheduler"
* tag 'sched-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Prevent cfs_rq from being unthrottled with zero runtime_remaining
Pull perf event fix from Ingo Molnar:
"Fix a system hang caused by cpu-clock events deadlock"
* tag 'perf-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix system hang caused by cpu-clock usage
Pull locking fix from Ingo Molnar:
"Fix (well, cut in half) a futex performance regression on PowerPC"
* tag 'locking-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Optimize per-cpu reference counting
Pull io_uring fix from Jens Axboe:
"Single fix in there, fixing an overflow in calculating the needed
segments for converting into a bvec array"
* tag 'io_uring-6.18-20251107' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
io_uring: fix regbuf vector size truncation
Pull xfs fixes from Carlos Maiolino:
"This contain fixes for the RT and zoned allocator, and a few fixes for
atomic writes"
* tag 'xfs-fixes-6.18-rc5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: free xfs_busy_extents structure when no RT extents are queued
xfs: fix zone selection in xfs_select_open_zone_mru
xfs: fix a rtgroup leak when xfs_init_zone fails
xfs: fix various problems in xfs_atomic_write_cow_iomap_begin
xfs: fix delalloc write failures in software-provided atomic writes
This reverts commit ebe7556050.
Tested the latest kernel on my GB203 and this seems to break it somehow.
Nov 09 04:16:14 bighp kernel: nouveau 0000:02:00.0: gsp: GSP-FMC boot failed (mbox: 0x0000000b)
Nov 09 04:16:14 bighp kernel: nouveau 0000:02:00.0: gsp: init failed, -5
Nov 09 04:16:14 bighp kernel: nouveau 0000:02:00.0: init failed with -5
Nov 09 04:16:14 bighp kernel: nouveau: drm:00000000:00000080: init failed with -5
Nov 09 04:16:14 bighp kernel: nouveau 0000:02:00.0: drm: Device allocation failed: -5
Nov 09 04:16:14 bighp kernel: nouveau 0000:02:00.0: probe with driver nouveau failed with error -5
Not sure why, I went over the patch and thought it should have worked, but there must be some
32-bit problem maybe in the FMC boot path.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Pull drm fixes from Dave Airlie:
"Back from travel, thanks to Simona for handling things. regular fixes,
seems about the right size, but spread out a bit.
amdgpu has the usual range of fixes, xe has a few fixes, and nouveau
has a couple of fixes, one for blackwell modifiers on 8/16 bit
surfaces.
Otherwise a few small fixes for mediatek, sched, imagination and
pixpaper.
sched:
- Fix deadlock
amdgpu:
- Reset fixes
- Misc fixes
- Panel scaling fixes
- HDMI fix
- S0ix fixes
- Hibernation fix
- Secure display fix
- Suspend fix
- MST fix
amdkfd:
- Process cleanup fix
xe:
- Fix missing synchronization on unbind
- Fix device shutdown when doing FLR
- Fix user fence signaling order
i915:
- Avoid lock inversion when pinning to GGTT on CHV/BXT+VTD
- Fix conversion between clock ticks and nanoseconds
mediatek:
- Disable AFBC support on Mediatek DRM driver
- Add pm_runtime support for GCE power control
imagination:
- kconfig: Fix dependencies
nouveau:
- Set DMA mask earlier
- Advertize correct modifiers for GB20x
pixpaper:
- kconfig: Fix dependencies"
* tag 'drm-fixes-2025-11-08' of https://gitlab.freedesktop.org/drm/kernel: (26 commits)
drm/xe: Enforce correct user fence signaling order using
drm/xe: Do clean shutdown also when using flr
drm/xe: Move declarations under conditional branch
drm/xe/guc: Synchronize Dead CT worker with unbind
drm/amd/display: Enable mst when it's detected but yet to be initialized
drm/amdgpu: Fix wait after reset sequence in S3
drm/amd: Fix suspend failure with secure display TA
drm/amdgpu: fix gpu page fault after hibernation on PF passthrough
drm/tiny: pixpaper: add explicit dependency on MMU
drm/nouveau: Advertise correct modifiers on GB20x
drm: define NVIDIA DRM format modifiers for GB20x
drm/nouveau: set DMA mask before creating the flush page
drm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb
drm/amd/display: Fix NULL deref in debugfs odm_combine_segments
drm/amdkfd: Don't clear PT after process killed
drm/amdgpu/smu: Handle S0ix for vangogh
drm/amdgpu: Drop PMFW RLC notifier from amdgpu_device_suspend()
drm/amd/display: Fix black screen with HDMI outputs
drm/amd/display: Don't stretch non-native images by default in eDP
drm/amd/pm: fix missing device_attr cleanup in amdgpu_pm_sysfs_init()
...
Pull parisc fix from Helge Deller:
- fix crash triggered by unaligned access in parisc unwinder
* tag 'parisc-for-6.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Avoid crash due to unaligned access in unwinder
Pull iommufd fixes from Jason Gunthorpe:
- Syzkaller found a case where maths overflows can cause divide by 0
- Typo in a compiler bug warning fix in the selftests broke the
selftests
- type1 compatability had a mismatch when unmapping an already unmapped
range, it should succeed
* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd:
iommufd: Make vfio_compat's unmap succeed if the range is already empty
iommufd/selftest: Fix ioctl return value in _test_cmd_trigger_vevents()
iommufd: Don't overflow during division for dirty tracking
Per Nathan, clang catches unused "static inline" functions in C files
since commit 6863f5643d ("kbuild: allow Clang to find unused static
inline functions for W=1 build").
Linus said:
> So I entirely ignore W=1 issues, because I think so many of the extra
> warnings are bogus.
>
> But if this one in particular is causing more problems than most -
> some teams do seem to use W=1 as part of their test builds - it's fine
> to send me a patch that just moves bad warnings to W=2.
>
> And if anybody uses W=2 for their test builds, that's THEIR problem..
Here is the change to bump the warning from W=1 to W=2.
Fixes: 6863f5643d ("kbuild: allow Clang to find unused static inline functions for W=1 build")
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20251106105000.2103276-1-andriy.shevchenko@linux.intel.com
[nathan: Adjust comment as well]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
SMB2_change_notify called smb2_validate_iov() but ignored the return
code, then kmemdup()ed using server provided OutputBufferOffset/Length.
Check the return of smb2_validate_iov() and bail out on error.
Discovered with help from the ZeroPath security tooling.
Signed-off-by: Joshua Rogers <linux@joshua.hu>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Cc: stable@vger.kernel.org
Fixes: e3e9463414 ("smb3: improve SMB3 change notification support")
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull gpio fixes from Bartosz Golaszewski:
- use the firmware node of the GPIO chip, not its label for software
node lookup
- fix invalid pointer access in GPIO debugfs
- drop unused functions from gpio-tb10x
- fix a regression in gpio-aggregator: restore the set_config()
callback in the driver
- correct schema $id path in ti,twl4030 DT bindings
* tag 'gpio-fixes-for-v6.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
gpio: tb10x: Drop unused tb10x_set_bits() function
gpio: aggregator: restore the set_config operation
gpiolib: fix invalid pointer access in debugfs
gpio: swnode: don't use the swnode's name as the key for GPIO lookup
dt-bindings: gpio: ti,twl4030: Correct the schema $id path
Pull tracing fixes from Steven Rostedt:
- Check for reader catching up in ring_buffer_map_get_reader()
If the reader catches up to the writer in the memory mapped ring
buffer then calling rb_get_reader_page() will return NULL as there's
no pages left. But this isn't checked for before calling
rb_get_reader_page() and the return of NULL causes a warning.
If it is detected that the reader caught up to the writer, then
simply exit the routine
- Fix memory leak in histogram create_field_var()
The couple of the error paths in create_field_var() did not properly
clean up what was allocated. Make sure everything is freed properly
on error
- Fix help message of tools latency_collector
The help message incorrectly stated that "-t" was the same as
"--threads" whereas "--threads" is actually represented by "-e"
* tag 'trace-v6.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/tools: Fix incorrcet short option in usage text for --threads
tracing: Fix memory leaks in create_field_var()
ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up
Pull slab fix from Vlastimil Babka:
- Fix for potential infinite loop in kmalloc_nolock() when debugging
is enabled for the cache (Vlastimil Babka)
* tag 'slab-for-6.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
slab: prevent infinite loop in kmalloc_nolock() with debugging
Pull io_uring fixes from Jens Axboe:
- Remove the sync refill API that was added in this release, in
anticipation of doing it in a better way for the next release
- Fix type extension for calculating size off nr_pages, like we do
in other spots
* tag 'io_uring-6.18-20251106' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
io_uring: fix types for region size calulation
io_uring/zcrx: remove sync refill uapi
Pull SCSI fixes from James Bottomley:
"All fixes in the UFS driver.
The big contributor to the diffstats is the Intel controller S0ix/S3
fix which has to special case the suspend/resume patch for intel
controllers in ufshcd-pci.c"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: ufs: core: Fix invalid probe error return value
scsi: ufs: ufs-pci: Set UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE for Intel ADL
scsi: ufs: core: Add a quirk to suppress link_startup_again
scsi: ufs: ufs-pci: Fix S0ix/S3 for Intel controllers
scsi: ufs: core: Revert "Make HID attributes visible"
scsi: ufs: core: Reduce link startup failure logging
scsi: ufs: core: Fix a race condition related to the "hid" attribute group
scsi: ufs: ufs-qcom: Fix UFS OCP issue during UFS power down (PC=3)
