Pull pidfs updates from Christian Brauner:
"Features:
- Allow handing out pidfds for reaped tasks for AF_UNIX SO_PEERPIDFD
socket option
SO_PEERPIDFD is a socket option that allows to retrieve a pidfd for
the process that called connect() or listen(). This is heavily used
to safely authenticate clients in userspace avoiding security bugs
due to pid recycling races (dbus, polkit, systemd, etc.)
SO_PEERPIDFD currently doesn't support handing out pidfds if the
sk->sk_peer_pid thread-group leader has already been reaped. In
this case it currently returns EINVAL. Userspace still wants to get
a pidfd for a reaped process to have a stable handle it can pass
on. This is especially useful now that it is possible to retrieve
exit information through a pidfd via the PIDFD_GET_INFO ioctl()'s
PIDFD_INFO_EXIT flag
Another summary has been provided by David Rheinsberg:
> A pidfd can outlive the task it refers to, and thus user-space
> must already be prepared that the task underlying a pidfd is
> gone at the time they get their hands on the pidfd. For
> instance, resolving the pidfd to a PID via the fdinfo must be
> prepared to read `-1`.
>
> Despite user-space knowing that a pidfd might be stale, several
> kernel APIs currently add another layer that checks for this. In
> particular, SO_PEERPIDFD returns `EINVAL` if the peer-task was
> already reaped, but returns a stale pidfd if the task is reaped
> immediately after the respective alive-check.
>
> This has the unfortunate effect that user-space now has two ways
> to check for the exact same scenario: A syscall might return
> EINVAL/ESRCH/... *or* the pidfd might be stale, even though
> there is no particular reason to distinguish both cases. This
> also propagates through user-space APIs, which pass on pidfds.
> They must be prepared to pass on `-1` *or* the pidfd, because
> there is no guaranteed way to get a stale pidfd from the kernel.
>
> Userspace must already deal with a pidfd referring to a reaped
> task as the task may exit and get reaped at any time will there
> are still many pidfds referring to it
In order to allow handing out reaped pidfd SO_PEERPIDFD needs to
ensure that PIDFD_INFO_EXIT information is available whenever a
pidfd for a reaped task is created by PIDFD_INFO_EXIT. The uapi
promises that reaped pidfds are only handed out if it is guaranteed
that the caller sees the exit information:
TEST_F(pidfd_info, success_reaped)
{
struct pidfd_info info = {
.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT,
};
/*
* Process has already been reaped and PIDFD_INFO_EXIT been set.
* Verify that we can retrieve the exit status of the process.
*/
ASSERT_EQ(ioctl(self->child_pidfd4, PIDFD_GET_INFO, &info), 0);
ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS));
ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT));
ASSERT_TRUE(WIFEXITED(info.exit_code));
ASSERT_EQ(WEXITSTATUS(info.exit_code), 0);
}
To hand out pidfds for reaped processes we thus allocate a pidfs
entry for the relevant sk->sk_peer_pid at the time the
sk->sk_peer_pid is stashed and drop it when the socket is
destroyed. This guarantees that exit information will always be
recorded for the sk->sk_peer_pid task and we can hand out pidfds
for reaped processes
- Hand a pidfd to the coredump usermode helper process
Give userspace a way to instruct the kernel to install a pidfd for
the crashing process into the process started as a usermode helper.
There's still tricky race-windows that cannot be easily or
sometimes not closed at all by userspace. There's various ways like
looking at the start time of a process to make sure that the
usermode helper process is started after the crashing process but
it's all very very brittle and fraught with peril
The crashed-but-not-reaped process can be killed by userspace
before coredump processing programs like systemd-coredump have had
time to manually open a PIDFD from the PID the kernel provides
them, which means they can be tricked into reading from an
arbitrary process, and they run with full privileges as they are
usermode helper processes
Even if that specific race-window wouldn't exist it's still the
safest and cleanest way to let the kernel provide the pidfd
directly instead of requiring userspace to do it manually. In
parallel with this commit we already have systemd adding support
for this in [1]
When the usermode helper process is forked we install a pidfd file
descriptor three into the usermode helper's file descriptor table
so it's available to the exec'd program
Since usermode helpers are either children of the system_unbound_wq
workqueue or kthreadd we know that the file descriptor table is
empty and can thus always use three as the file descriptor number
Note, that we'll install a pidfd for the thread-group leader even
if a subthread is calling do_coredump(). We know that task linkage
hasn't been removed yet and even if this @current isn't the actual
thread-group leader we know that the thread-group leader cannot be
reaped until
@current has exited
- Allow telling when a task has not been found from finding the wrong
task when creating a pidfd
We currently report EINVAL whenever a struct pid has no tasked
attached anymore thereby conflating two concepts:
(1) The task has already been reaped
(2) The caller requested a pidfd for a thread-group leader but the
pid actually references a struct pid that isn't used as a
thread-group leader
This is causing issues for non-threaded workloads as in where they
expect ESRCH to be reported, not EINVAL
So allow userspace to reliably distinguish between (1) and (2)
- Make it possible to detect when a pidfs entry would outlive the
struct pid it pinned
- Add a range of new selftests
Cleanups:
- Remove unneeded NULL check from pidfd_prepare() for passed struct
pid
- Avoid pointless reference count bump during release_task()
Fixes:
- Various fixes to the pidfd and coredump selftests
- Fix error handling for replace_fd() when spawning coredump usermode
helper"
* tag 'vfs-6.16-rc1.pidfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
pidfs: detect refcount bugs
coredump: hand a pidfd to the usermode coredump helper
coredump: fix error handling for replace_fd()
pidfs: move O_RDWR into pidfs_alloc_file()
selftests: coredump: Raise timeout to 2 minutes
selftests: coredump: Fix test failure for slow machines
selftests: coredump: Properly initialize pointer
net, pidfs: enable handing out pidfds for reaped sk->sk_peer_pid
pidfs: get rid of __pidfd_prepare()
net, pidfs: prepare for handing out pidfds for reaped sk->sk_peer_pid
pidfs: register pid in pidfs
net, pidfd: report EINVAL for ESRCH
release_task: kill the no longer needed get/put_pid(thread_pid)
pidfs: ensure consistent ENOENT/ESRCH reporting
exit: move wake_up_all() pidfd waiters into __unhash_process()
selftest/pidfd: add test for thread-group leader pidfd open for thread
pidfd: improve uapi when task isn't found
pidfd: remove unneeded NULL check from pidfd_prepare()
selftests/pidfd: adapt to recent changes
Pull vfs mount updates from Christian Brauner:
"This contains minor mount updates for this cycle:
- mnt->mnt_devname can never be NULL so simplify the code handling
that case
- Add a comment about concurrent changes during statmount() and
listmount()
- Update the STATMOUNT_SUPPORTED macro
- Convert mount flags to an enum"
* tag 'vfs-6.16-rc1.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
statmount: update STATMOUNT_SUPPORTED macro
fs: convert mount flags to enum
->mnt_devname is never NULL
mount: add a comment about concurrent changes with statmount()/listmount()
Pull vfs freezing updates from Christian Brauner:
"This contains various filesystem freezing related work for this cycle:
- Allow the power subsystem to support filesystem freeze for suspend
and hibernate.
Now all the pieces are in place to actually allow the power
subsystem to freeze/thaw filesystems during suspend/resume.
Filesystems are only frozen and thawed if the power subsystem does
actually own the freeze.
If the filesystem is already frozen by the time we've frozen all
userspace processes we don't care to freeze it again. That's
userspace's job once the process resumes. We only actually freeze
filesystems if we absolutely have to and we ignore other failures
to freeze.
We could bubble up errors and fail suspend/resume if the error
isn't EBUSY (aka it's already frozen) but I don't think that this
is worth it. Filesystem freezing during suspend/resume is
best-effort. If the user has 500 ext4 filesystems mounted and 4
fail to freeze for whatever reason then we simply skip them.
What we have now is already a big improvement and let's see how we
fare with it before making our lives even harder (and uglier) than
we have to.
- Allow efivars to support freeze and thaw
Allow efivarfs to partake to resync variable state during system
hibernation and suspend. Add freeze/thaw support.
This is a pretty straightforward implementation. We simply add
regular freeze/thaw support for both userspace and the kernel.
efivars is the first pseudofilesystem that adds support for
filesystem freezing and thawing.
The simplicity comes from the fact that we simply always resync
variable state after efivarfs has been frozen. It doesn't matter
whether that's because of suspend, userspace initiated freeze or
hibernation. Efivars is simple enough that it doesn't matter that
we walk all dentries. There are no directories and there aren't
insane amounts of entries and both freeze/thaw are already
heavy-handed operations. If userspace initiated a freeze/thaw cycle
they would need CAP_SYS_ADMIN in the initial user namespace (as
that's where efivarfs is mounted) so it can't be triggered by
random userspace. IOW, we really really don't care"
* tag 'vfs-6.16-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
f2fs: fix freezing filesystem during resize
kernfs: add warning about implementing freeze/thaw
efivarfs: support freeze/thaw
power: freeze filesystems during suspend/resume
libfs: export find_next_child()
super: add filesystem freezing helpers for suspend and hibernate
gfs2: pass through holder from the VFS for freeze/thaw
super: use common iterator (Part 2)
super: use a common iterator (Part 1)
super: skip dying superblocks early
super: simplify user_get_super()
super: remove pointless s_root checks
fs: allow all writers to be frozen
locking/percpu-rwsem: add freezable alternative to down_read
Pull misc vfs updates from Christian Brauner:
"This contains the usual selections of misc updates for this cycle.
Features:
- Use folios for symlinks in the page cache
FUSE already uses folios for its symlinks. Mirror that conversion
in the generic code and the NFS code. That lets us get rid of a few
folio->page->folio conversions in this path, and some of the few
remaining users of read_cache_page() / read_mapping_page()
- Try and make a few filesystem operations killable on the VFS
inode->i_mutex level
- Add sysctl vfs_cache_pressure_denom for bulk file operations
Some workloads need to preserve more dentries than we currently
allow through out sysctl interface
A HDFS servers with 12 HDDs per server, on a HDFS datanode startup
involves scanning all files and caching their metadata (including
dentries and inodes) in memory. Each HDD contains approximately 2
million files, resulting in a total of ~20 million cached dentries
after initialization
To minimize dentry reclamation, they set vfs_cache_pressure to 1.
Despite this configuration, memory pressure conditions can still
trigger reclamation of up to 50% of cached dentries, reducing the
cache from 20 million to approximately 10 million entries. During
the subsequent cache rebuild period, any HDFS datanode restart
operation incurs substantial latency penalties until full cache
recovery completes
To maintain service stability, more dentries need to be preserved
during memory reclamation. The current minimum reclaim ratio (1/100
of total dentries) remains too aggressive for such workload. This
patch introduces vfs_cache_pressure_denom for more granular cache
pressure control
The configuration [vfs_cache_pressure=1,
vfs_cache_pressure_denom=10000] effectively maintains the full 20
million dentry cache under memory pressure, preventing datanode
restart performance degradation
- Avoid some jumps in inode_permission() using likely()/unlikely()
- Avid a memory access which is most likely a cache miss when
descending into devcgroup_inode_permission()
- Add fastpath predicts for stat() and fdput()
- Anonymous inodes currently don't come with a proper mode causing
issues in the kernel when we want to add useful VFS debug assert.
Fix that by giving them a proper mode and masking it off when we
report it to userspace which relies on them not having any mode
- Anonymous inodes currently allow to change inode attributes because
the VFS falls back to simple_setattr() if i_op->setattr isn't
implemented. This means the ownership and mode for every single
user of anon_inode_inode can be changed. Block that as it's either
useless or actively harmful. If specific ownership is needed the
respective subsystem should allocate anonymous inodes from their
own private superblock
- Raise SB_I_NODEV and SB_I_NOEXEC on the anonymous inode superblock
- Add proper tests for anonymous inode behavior
- Make it easy to detect proper anonymous inodes and to ensure that
we can detect them in codepaths such as readahead()
Cleanups:
- Port pidfs to the new anon_inode_{g,s}etattr() helpers
- Try to remove the uselib() system call
- Add unlikely branch hint return path for poll
- Add unlikely branch hint on return path for core_sys_select
- Don't allow signals to interrupt getdents copying for fuse
- Provide a size hint to dir_context for during readdir()
- Use writeback_iter directly in mpage_writepages
- Update compression and mtime descriptions in initramfs
documentation
- Update main netfs API document
- Remove useless plus one in super_cache_scan()
- Remove unnecessary NULL-check guards during setns()
- Add separate separate {get,put}_cgroup_ns no-op cases
Fixes:
- Fix typo in root= kernel parameter description
- Use KERN_INFO for infof()|info_plog()|infofc()
- Correct comments of fs_validate_description()
- Mark an unlikely if condition with unlikely() in
vfs_parse_monolithic_sep()
- Delete macro fsparam_u32hex()
- Remove unused and problematic validate_constant_table()
- Fix potential unsigned integer underflow in fs_name()
- Make file-nr output the total allocated file handles"
* tag 'vfs-6.16-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (43 commits)
fs: Pass a folio to page_put_link()
nfs: Use a folio in nfs_get_link()
fs: Convert __page_get_link() to use a folio
fs/read_write: make default_llseek() killable
fs/open: make do_truncate() killable
fs/open: make chmod_common() and chown_common() killable
include/linux/fs.h: add inode_lock_killable()
readdir: supply dir_context.count as readdir buffer size hint
vfs: Add sysctl vfs_cache_pressure_denom for bulk file operations
fuse: don't allow signals to interrupt getdents copying
Documentation: fix typo in root= kernel parameter description
include/cgroup: separate {get,put}_cgroup_ns no-op case
kernel/nsproxy: remove unnecessary guards
fs: use writeback_iter directly in mpage_writepages
fs: remove useless plus one in super_cache_scan()
fs: add S_ANON_INODE
fs: remove uselib() system call
device_cgroup: avoid access to ->i_rdev in the common case in devcgroup_inode_permission()
fs/fs_parse: Remove unused and problematic validate_constant_table()
fs: touch up predicts in inode_permission()
...
Pull vfs mount api conversions from Christian Brauner:
"This converts the bfs and omfs filesystems to the new mount api"
* tag 'vfs-6.16-rc1.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
omfs: convert to new mount API
bfs: convert bfs to use the new mount api
Pull final writepage conversion from Christian Brauner:
"This converts vboxfs from ->writepage() to ->writepages().
This was the last user of the ->writepage() method. So remove
->writepage() completely and all references to it"
* tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: Remove aops->writepage
mm: Remove swap_writepage() and shmem_writepage()
ttm: Call shmem_writeout() from ttm_backup_backup_page()
i915: Use writeback_iter()
shmem: Add shmem_writeout()
writeback: Remove writeback_use_writepage()
migrate: Remove call to ->writepage
vboxsf: Convert to writepages
9p: Add a migrate_folio method
Pull vfs directory lookup updates from Christian Brauner:
"This contains cleanups for the lookup_one*() family of helpers.
We expose a set of functions with names containing "lookup_one_len"
and others without the "_len". This difference has nothing to do with
"len". It's rater a historical accident that can be confusing.
The functions without "_len" take a "mnt_idmap" pointer. This is found
in the "vfsmount" and that is an important question when choosing
which to use: do you have a vfsmount, or are you "inside" the
filesystem. A related question is "is permission checking relevant
here?".
nfsd and cachefiles *do* have a vfsmount but *don't* use the non-_len
functions. They pass nop_mnt_idmap and refuse to work on filesystems
which have any other idmap.
This work changes nfsd and cachefile to use the lookup_one family of
functions and to explictily pass &nop_mnt_idmap which is consistent
with all other vfs interfaces used where &nop_mnt_idmap is explicitly
passed.
The remaining uses of the "_one" functions do not require permission
checks so these are renamed to be "_noperm" and the permission
checking is removed.
This series also changes these lookup function to take a qstr instead
of separate name and len. In many cases this simplifies the call"
* tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
VFS: change lookup_one_common and lookup_noperm_common to take a qstr
Use try_lookup_noperm() instead of d_hash_and_lookup() outside of VFS
VFS: rename lookup_one_len family to lookup_noperm and remove permission check
cachefiles: Use lookup_one() rather than lookup_one_len()
nfsd: Use lookup_one() rather than lookup_one_len()
VFS: improve interface for lookup_one functions
This is kind of last-minute, but Al Viro reported that the new
FOP_DONTCACHE flag causes memory corruption due to use-after-free
issues.
This was triggered by commit 974c5e6139 ("xfs: flag as supporting
FOP_DONTCACHE"), but that is not the underlying bug - it is just the
first user of the flag.
Vlastimil Babka suspects the underlying problem stems from the
folio_end_writeback() logic introduced in commit fb7d3bc414
("mm/filemap: drop streaming/uncached pages when writeback completes").
The most straightforward fix would be to just revert the commit that
exposed this, but Matthew Wilcox points out that other filesystems are
also starting to enable the FOP_DONTCACHE logic, so this instead
disables that bit globally for now.
The fix will hopefully end up being trivial and we can just re-enable
this logic after more testing, but until such a time we'll have to
disable the new FOP_DONTCACHE flag.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/all/20250525083209.GS2023217@ZenIV/
Triggered-by: 974c5e6139 ("xfs: flag as supporting FOP_DONTCACHE")
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull hotfixes from Andrew Morton:
"22 hotfixes.
13 are cc:stable and the remainder address post-6.14 issues or aren't
considered necessary for -stable kernels. 19 are for MM"
* tag 'mm-hotfixes-stable-2025-05-25-00-58' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
mailmap: add Jarkko's employer email address
mm: fix copy_vma() error handling for hugetlb mappings
memcg: always call cond_resched() after fn()
mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios
mm: vmalloc: only zero-init on vrealloc shrink
mm: vmalloc: actually use the in-place vrealloc region
alloc_tag: allocate percpu counters for module tags dynamically
module: release codetag section when module load fails
mm/cma: make detection of highmem_start more robust
MAINTAINERS: add mm memory policy section
MAINTAINERS: add mm ksm section
kasan: avoid sleepable page allocation from atomic context
highmem: add folio_test_partial_kmap()
MAINTAINERS: add hung-task detector section
taskstats: fix struct taskstats breaks backward compatibility since version 15
mm/truncate: fix out-of-bounds when doing a right-aligned split
MAINTAINERS: add mm reclaim section
MAINTAINERS: update page allocator section
mm: fix VM_UFFD_MINOR == VM_SHADOW_STACK on USERFAULTFD=y && ARM64_GCS=y
mm: mmap: map MAP_STACK to VM_NOHUGEPAGE only if THP is enabled
...
If, during a mremap() operation for a hugetlb-backed memory mapping,
copy_vma() fails after the source vma has been duplicated and opened (ie.
vma_link() fails), the error is handled by closing the new vma. This
updates the hugetlbfs reservation counter of the reservation map which at
this point is referenced by both the source vma and the new copy. As a
result, once the new vma has been freed and copy_vma() returns, the
reservation counter for the source vma will be incorrect.
This patch addresses this corner case by clearing the hugetlb private page
reservation reference for the new vma and decrementing the reference
before closing the vma, so that vma_close() won't update the reservation
counter. This is also what copy_vma_and_data() does with the source vma
if copy_vma() succeeds, so a helper function has been added to do the
fixup in both functions.
The issue was reported by a private syzbot instance and can be reproduced
using the C reproducer in [1]. It's also a possible duplicate of public
syzbot report [2]. The WARNING report is:
============================================================
page_counter underflow: -1024 nr_pages=1024
WARNING: CPU: 0 PID: 3287 at mm/page_counter.c:61 page_counter_cancel+0xf6/0x120
Modules linked in:
CPU: 0 UID: 0 PID: 3287 Comm: repro__WARNING_ Not tainted 6.15.0-rc7+ #54 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-2-gc13ff2cd-prebuilt.qemu.org 04/01/2014
RIP: 0010:page_counter_cancel+0xf6/0x120
Code: ff 5b 41 5e 41 5f 5d c3 cc cc cc cc e8 f3 4f 8f ff c6 05 64 01 27 06 01 48 c7 c7 60 15 f8 85 48 89 de 4c 89 fa e8 2a a7 51 ff <0f> 0b e9 66 ff ff ff 44 89 f9 80 e1 07 38 c1 7c 9d 4c 81
RSP: 0018:ffffc900025df6a0 EFLAGS: 00010246
RAX: 2edfc409ebb44e00 RBX: fffffffffffffc00 RCX: ffff8880155f0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff81c4a23c R09: 1ffff1100330482a
R10: dffffc0000000000 R11: ffffed100330482b R12: 0000000000000000
R13: ffff888058a882c0 R14: ffff888058a882c0 R15: 0000000000000400
FS: 0000000000000000(0000) GS:ffff88808fc53000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b33e0 CR3: 00000000076d6000 CR4: 00000000000006f0
Call Trace:
<TASK>
page_counter_uncharge+0x33/0x80
hugetlb_cgroup_uncharge_counter+0xcb/0x120
hugetlb_vm_op_close+0x579/0x960
? __pfx_hugetlb_vm_op_close+0x10/0x10
remove_vma+0x88/0x130
exit_mmap+0x71e/0xe00
? __pfx_exit_mmap+0x10/0x10
? __mutex_unlock_slowpath+0x22e/0x7f0
? __pfx_exit_aio+0x10/0x10
? __up_read+0x256/0x690
? uprobe_clear_state+0x274/0x290
? mm_update_next_owner+0xa9/0x810
__mmput+0xc9/0x370
exit_mm+0x203/0x2f0
? __pfx_exit_mm+0x10/0x10
? taskstats_exit+0x32b/0xa60
do_exit+0x921/0x2740
? do_raw_spin_lock+0x155/0x3b0
? __pfx_do_exit+0x10/0x10
? __pfx_do_raw_spin_lock+0x10/0x10
? _raw_spin_lock_irq+0xc5/0x100
do_group_exit+0x20c/0x2c0
get_signal+0x168c/0x1720
? __pfx_get_signal+0x10/0x10
? schedule+0x165/0x360
arch_do_signal_or_restart+0x8e/0x7d0
? __pfx_arch_do_signal_or_restart+0x10/0x10
? __pfx___se_sys_futex+0x10/0x10
syscall_exit_to_user_mode+0xb8/0x2c0
do_syscall_64+0x75/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x422dcd
Code: Unable to access opcode bytes at 0x422da3.
RSP: 002b:00007ff266cdb208 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007ff266cdbcdc RCX: 0000000000422dcd
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00000000004c7bec
RBP: 00007ff266cdb220 R08: 203a6362696c6720 R09: 203a6362696c6720
R10: 0000200000c00000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000002 R14: 00007ffe1cb5f520 R15: 00007ff266cbb000
</TASK>
============================================================
Link: https://lkml.kernel.org/r/20250523-warning_in_page_counter_cancel-v2-1-b6df1a8cfefd@igalia.com
Link: https://people.igalia.com/rcn/kernel_logs/20250422__WARNING_in_page_counter_cancel__repro.c [1]
Link: https://lore.kernel.org/all/67000a50.050a0220.49194.048d.GAE@google.com/ [2]
Signed-off-by: Ricardo Cañuelo Navarro <rcn@igalia.com>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Florent Revest <revest@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
I am seeing soft lockup on certain machine types when a cgroup OOMs. This
is happening because killing the process in certain machine might be very
slow, which causes the soft lockup and RCU stalls. This happens usually
when the cgroup has MANY processes and memory.oom.group is set.
Example I am seeing in real production:
[462012.244552] Memory cgroup out of memory: Killed process 3370438 (crosvm) ....
....
[462037.318059] Memory cgroup out of memory: Killed process 4171372 (adb) ....
[462037.348314] watchdog: BUG: soft lockup - CPU#64 stuck for 26s! [stat_manager-ag:1618982]
....
Quick look at why this is so slow, it seems to be related to serial flush
for certain machine types. For all the crashes I saw, the target CPU was
at console_flush_all().
In the case above, there are thousands of processes in the cgroup, and it
is soft locking up before it reaches the 1024 limit in the code (which
would call the cond_resched()). So, cond_resched() in 1024 blocks is not
sufficient.
Remove the counter-based conditional rescheduling logic and call
cond_resched() unconditionally after each task iteration, after fn() is
called. This avoids the lockup independently of how slow fn() is.
Link: https://lkml.kernel.org/r/20250523-memcg_fix-v1-1-ad3eafb60477@debian.org
Fixes: ade81479c7 ("memcg: fix soft lockup in the OOM process")
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Rik van Riel <riel@surriel.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Michael van der Westhuizen <rmikey@meta.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a module gets unloaded it checks whether any of its tags are still in
use and if so, we keep the memory containing module's allocation tags
alive until all tags are unused. However percpu counters referenced by
the tags are freed by free_module(). This will lead to UAF if the memory
allocated by a module is accessed after module was unloaded.
To fix this we allocate percpu counters for module allocation tags
dynamically and we keep it alive for tags which are still in use after
module unloading. This also removes the requirement of a larger
PERCPU_MODULE_RESERVE when memory allocation profiling is enabled because
percpu memory for counters does not need to be reserved anymore.
Link: https://lkml.kernel.org/r/20250517000739.5930-1-surenb@google.com
Fixes: 0db6f8d782 ("alloc_tag: load module tags into separate contiguous memory")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/all/20250516131246.6244-1-00107082@163.com/
Tested-by: David Wang <00107082@163.com>
Cc: Christoph Lameter (Ampere) <cl@gentwo.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pratyush Yadav reports the following crash:
------------[ cut here ]------------
kernel BUG at arch/x86/mm/physaddr.c:23!
ception 0x06 IP 10:ffffffff812ebbf8 error 0 cr2 0xffff88903ffff000
CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.15.0-rc6+ #231 PREEMPT(undef)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
RIP: 0010:__phys_addr+0x58/0x60
Code: 01 48 89 c2 48 d3 ea 48 85 d2 75 05 e9 91 52 cf 00 0f 0b 48 3d ff ff ff 1f 77 0f 48 8b 05 20 54 55 01 48 01 d0 e9 78 52 cf 00 <0f> 0b 90 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0000:ffffffff82803dd8 EFLAGS: 00010006 ORIG_RAX: 0000000000000000
RAX: 000000007fffffff RBX: 00000000ffffffff RCX: 0000000000000000
RDX: 000000007fffffff RSI: 0000000280000000 RDI: ffffffffffffffff
RBP: ffffffff82803e68 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff83153180 R11: ffffffff82803e48 R12: ffffffff83c9aed0
R13: 0000000000000000 R14: 0000001040000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:0000000000000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88903ffff000 CR3: 0000000002838000 CR4: 00000000000000b0
Call Trace:
<TASK>
? __cma_declare_contiguous_nid+0x6e/0x340
? cma_declare_contiguous_nid+0x33/0x70
? dma_contiguous_reserve_area+0x2f/0x70
? setup_arch+0x6f1/0x870
? start_kernel+0x52/0x4b0
? x86_64_start_reservations+0x29/0x30
? x86_64_start_kernel+0x7c/0x80
? common_startup_64+0x13e/0x141
The reason is that __cma_declare_contiguous_nid() does:
highmem_start = __pa(high_memory - 1) + 1;
If dma_contiguous_reserve_area() (or any other CMA declaration) is
called before free_area_init(), high_memory is uninitialized. Without
CONFIG_DEBUG_VIRTUAL, it will likely work but use the wrong value for
highmem_start.
The issue occurs because commit e120d1bc12 ("arch, mm: set high_memory
in free_area_init()") moved initialization of high_memory after the call
to dma_contiguous_reserve() -> __cma_declare_contiguous_nid() on several
architectures.
In the case CONFIG_HIGHMEM is enabled, some architectures that actually
support HIGHMEM (arm, powerpc and x86) have initialization of high_memory
before a possible call to __cma_declare_contiguous_nid() and some
initialized high_memory late anyway (arc, csky, microblase, mips, sparc,
xtensa) even before the commit e120d1bc12 so they are fine with using
uninitialized value of high_memory.
And in the case CONFIG_HIGHMEM is disabled high_memory essentially becomes
the first address after memory end, so instead of relying on high_memory
to calculate highmem_start use memblock_end_of_DRAM() and eliminate the
dependency of CMA area creation on high_memory in majority of
configurations.
Link: https://lkml.kernel.org/r/20250519171805.1288393-1-rppt@kernel.org
Fixes: e120d1bc12 ("arch, mm: set high_memory in free_area_init()")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reported-by: Pratyush Yadav <ptyadav@amazon.de>
Tested-by: Pratyush Yadav <ptyadav@amazon.de>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull input fixes from Dmitry Torokhov:
- even more Xbox controllers added to xpad driver: Turtle Beach Recon
Wired Controller, Turtle Beach Stealth Ultra, and PowerA Wired
Controller
- a fix to Synaptics RMI driver to not crash if controller reports
unsupported version of F34 (firmware flash) function
* tag 'input-for-v6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: synaptics-rmi - fix crash with unsupported versions of F34
Input: xpad - add more controllers
Pull spi fixes from Mark Brown:
"A few final fixes for v6.15, some driver fixes for the Freescale DSPI
driver pulled over from their vendor code and another instance of the
fixes Greg has been sending throughout the kernel for constification
of the bus_type in driver core match() functions"
* tag 'spi-fix-v6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: spi-fsl-dspi: Reset SR flags before sending a new message
spi: spi-fsl-dspi: Halt the module after a new message transfer
spi: spi-fsl-dspi: restrict register range for regmap access
spi: use container_of_cont() for to_spi_device()
Pull iommu fix from Joerg Roedel:
- core: skip PASID validation for devices without PASID support
* tag 'iommu-fixes-v6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux:
iommu: Skip PASID validation for devices without PASID capability
Pull drm fixes from Dave Airlie:
"Weekly drm fixes pull, on target to be quiet, just one amdgpu, one
edid and a few minor xe fixes.
edid:
- fix HDR metadata reset
amdgpu:
- Hibernate fix
xe:
- Make sure to check all forcewakes when dumping mocs
- Fix wrong use of read64 on 32b register
- Synchronize Panther Lake PCI IDs"
* tag 'drm-fixes-2025-05-24' of https://gitlab.freedesktop.org/drm/kernel:
drm/xe/ptl: Update the PTL pci id table
drm/xe: Use xe_mmio_read32() to read mtcfg register
drm/xe/mocs: Check if all domains awake
Revert "drm/amd: Keep display off while going into S4"
drm/edid: fixed the bug that hdr metadata was not reset
Pull thermal control fix from Rafael Wysocki:
"This fixes a coding mistake in the x86_pkg_temp_thermal Intel thermal
driver that was introduced by an incorrect conflict resolution during
a merge (Zhang Rui)"
* tag 'thermal-6.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
thermal: intel: x86_pkg_temp_thermal: Fix bogus trip temperature
Pull smb server fixes from Steve French:
- Fix for rename regression due to the recent VFS lookup changes
- Fix write failure
- locking fix for oplock handling
* tag 'v6.15-rc8-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: use list_first_entry_or_null for opinfo_get_list()
ksmbd: fix rename failure
ksmbd: fix stream write failure
Pull SoC fixes from Arnd Bergmann:
"A few last minute fixes:
- two driver fixes for samsung/google platforms, both addressing
mistakes in changes from the 6.15 merge window
- a revert for an allwinner devicetree change that caused problems
- a fix for an older regression with the LEDs on Marvell Armada 3720
- a defconfig change to enable chacha20 again after a crypto
subsystem change in 6.15 inadventently turned it off"
* tag 'soc-fixes-6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
arm64: defconfig: Ensure CRYPTO_CHACHA20_NEON is selected
arm64: dts: marvell: uDPU: define pinctrl state for alarm LEDs
Revert "arm64: dts: allwinner: h6: Use RSB for AXP805 PMIC connection"
soc: samsung: usi: prevent wrong bits inversion during unconfiguring
firmware: exynos-acpm: check saved RX before bailing out on empty RX queue
Pull vfs fixes from Christian Brauner:
"This contains a small set of fixes for the blocking buffer lookup
conversion done earlier this cycle.
It adds a missing conversion in the getblk slowpath and a few minor
optimizations and cleanups"
* tag 'vfs-6.15-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs/buffer: optimize discard_buffer()
fs/buffer: remove superfluous statements
fs/buffer: avoid redundant lookup in getblk slowpath
fs/buffer: use sleeping lookup in __getblk_slowpath()
In prior kernel versions (5.8-6.8), commit 9f6c61f96f ("proc/mounts:
add cursor") introduced MNT_CURSOR, a flag used by readers from
/proc/mounts to keep their place while reading the file. Later, commit
2eea9ce431 ("mounts: keep list of mounts in an rbtree") removed this
flag and its value has since been repurposed.
For debuggers iterating over the list of mounts, cursors should be
skipped as they are irrelevant. Detecting whether an element is a cursor
can be difficult. Since the MNT_CURSOR flag is a preprocessor constant,
it's not present in debuginfo, and since its value is repurposed, we
cannot hard-code it. For this specific issue, cursors are possible to
detect in other ways, but ideally, we would be able to read the mount
flag definitions out of the debuginfo. For that reason, convert the
mount flags to an enum.
Link: https://github.com/osandov/drgn/pull/496
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/20250507223402.2795029-1-stephen.s.brennan@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
The ARL requires that the GMA and NPU devices both be in D3Hot in order
for PC10 and S0iX to be achieved in S2idle. The original ARL-H/U addition
to the intel_pmc_core driver attempted to do this by switching them to D3
in the init and resume calls of the intel_pmc_core driver.
The problem is the ARL-H/U have a different NPU device and thus are not
being properly set and thus S0iX does not work properly in ARL-H/U. This
patch creates a new ARL-H specific device id that is correct and also
adds the D3 fixup to the suspend callback. This way if the PCI devies
drop from D3 to D0 after resume they can be corrected for the next
suspend. Thus there is no dropout in S0iX.
Fixes: bd820906ea ("platform/x86/intel/pmc: Add Arrow Lake U/H support to intel_pmc_core driver")
Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Link: https://lore.kernel.org/r/a61f78be45c13f39e122dcc684b636f4b21e79a0.1747737446.git.todd.e.brandt@intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Pull bcachefs fixes from Kent Overstreet:
"Small stuff, main ones users will be interested in:
- Couple more casefolding fixes; we can now detect and repair
casefolded dirents in non-casefolded dir and vice versa
- Fix for massive write inflation with mmapped io, which hit certain
databases"
* tag 'bcachefs-2025-05-22' of git://evilpiepirate.org/bcachefs:
bcachefs: Check for casefolded dirents in non casefolded dirs
bcachefs: Fix bch2_dirent_create_snapshot() for casefolding
bcachefs: Fix casefold opt via xattr interface
bcachefs: mkwrite() now only dirties one page
bcachefs: fix extent_has_stripe_ptr()
bcachefs: Fix bch2_btree_path_traverse_cached() when paths realloced
Pull block fixes from Jens Axboe:
- Fix for a regression with setting up loop on a file system
without ->write_iter()
- Fix for an nvme sysfs regression
* tag 'block-6.15-20250522' of git://git.kernel.dk/linux:
nvme: avoid creating multipath sysfs group under namespace path devices
loop: don't require ->write_iter for writable files in loop_configure
Pull io_uring fixes from Jens Axboe:
- Kill a duplicate function definition, which can cause linking issues
in certain .config configurations. Introduced in this cycle.
- Fix for a potential overflow CQE reordering issue if a re-schedule is
done during posting. Heading to stable.
- Fix for an issue with recv bundles, where certain conditions can lead
to gaps in the buffers, where a contiguous buffer range was expected.
Heading to stable.
* tag 'io_uring-6.15-20250522' of git://git.kernel.dk/linux:
io_uring/net: only retry recv bundle for a full transfer
io_uring: fix overflow resched cqe reordering
io_uring/cmd: axe duplicate io_uring_cmd_import_fixed_vec() declaration
Pull smb client fixes from Steve French:
- Two fixes for use after free in readdir code paths
* tag '6.15-rc8-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: Reset all search buffer pointers when releasing buffer
smb: client: Fix use-after-free in cifs_fill_dirent
Pull networking fixes from Paolo Abeni:
"This is somewhat larger than what I hoped for, with a few PRs from
subsystems and follow-ups for the recent netdev locking changes,
anyhow there are no known pending regressions.
Including fixes from bluetooth, ipsec and CAN.
Current release - regressions:
- eth: team: grab team lock during team_change_rx_flags
- eth: bnxt_en: fix netdev locking in ULP IRQ functions
Current release - new code bugs:
- xfrm: ipcomp: fix truesize computation on receive
- eth: airoha: fix page recycling in airoha_qdma_rx_process()
Previous releases - regressions:
- sched: hfsc: fix qlen accounting bug when using peek in
hfsc_enqueue()
- mr: consolidate the ipmr_can_free_table() checks.
- bridge: netfilter: fix forwarding of fragmented packets
- xsk: bring back busy polling support in XDP_COPY
- can:
- add missing rcu read protection for procfs content
- kvaser_pciefd: force IRQ edge in case of nested IRQ
Previous releases - always broken:
- xfrm: espintcp: remove encap socket caching to avoid reference leak
- bluetooth: use skb_pull to avoid unsafe access in QCA dump handling
- eth: idpf:
- fix null-ptr-deref in idpf_features_check
- fix idpf_vport_splitq_napi_poll()
- eth: hibmcge: fix wrong ndo.open() after reset fail issue"
* tag 'net-6.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (40 commits)
octeontx2-af: Fix APR entry mapping based on APR_LMT_CFG
octeontx2-af: Set LMT_ENA bit for APR table entries
net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done
octeontx2-pf: Avoid adding dcbnl_ops for LBK and SDP vf
selftests/tc-testing: Add an HFSC qlen accounting test
sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()
idpf: fix idpf_vport_splitq_napi_poll()
net: hibmcge: fix wrong ndo.open() after reset fail issue.
net: hibmcge: fix incorrect statistics update issue
xsk: Bring back busy polling support in XDP_COPY
can: slcan: allow reception of short error messages
net: lan743x: Restore SGMII CTRL register on resume
bnxt_en: Fix netdev locking in ULP IRQ functions
MAINTAINERS: Drop myself to reviewer for ravb driver
net: dwmac-sun8i: Use parsed internal PHY address instead of 1
net: ethernet: ti: am65-cpsw: Lower random mac address error print to info
can: kvaser_pciefd: Continue parsing DMA buf after dropped RX
can: kvaser_pciefd: Fix echo_skb race
can: kvaser_pciefd: Force IRQ edge in case of nested IRQ
idpf: fix null-ptr-deref in idpf_features_check
...
Pull pin control fixes from Linus Walleij:
"This deals with a crash in the Qualcomm pin controller GPIO
parts when using hogs.
The first patch to gpiolib makes gpiochip_line_is_valid()
NULL-tolerant.
The second patch fixes the actual problem"
* tag 'pinctrl-v6.15-4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
pinctrl: qcom: switch to devm_register_sys_off_handler()
gpiolib: don't crash on enabling GPIO HOG pins
Pull sound fixes from Takashi Iwai:
"A collection of small fixes for 6.15 final. It became slightly a
higher amount than expected, but all look easy and safe to apply:
- A fix for PCM core race spotted by fuzzing
- ASoC topology fix for single DAI link
- UAF fix for ASoC SOF Intel HD-audio at reloading
- ASoC SOF Intel and Mediatek fixes
- Trivial HD-audio quirks as usual"
* tag 'sound-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/realtek - Add new HP ZBook laptop with micmute led fixup
ALSA: hda/realtek: Add support for HP Agusta using CS35L41 HDA
ALSA: hda/realtek: Add quirk for Lenovo Yoga Pro 7 14ASP10
ALSA: hda/realtek - restore auto-mute mode for Dell Chrome platform
ALSA: pcm: Fix race of buffer access at PCM OSS layer
ASoC: SOF: Intel: hda: Fix UAF when reloading module
ASoc: SOF: topology: connect DAI to a single DAI link
ASoC: SOF: Intel: hda-bus: Use PIO mode on ACE2+ platforms
ASoC: SOF: ipc4-pcm: Delay reporting is only supported for playback direction
ASoC: SOF: ipc4-control: Use SOF_CTRL_CMD_BINARY as numid for bytes_ext
ASoC: mediatek: mt8188-mt6359: Depend on MT6359_ACCDET set or disabled
ASoC: mediatek: mt8188-mt6359: select CONFIG_SND_SOC_MT6359_ACCDET
Pull NVMe fix from Christoph:
"nvme fixes for Linux 6.15
- do not create the newly added multipath sysfs group for
non-multipath nodes (Nilay Shroff)"
* tag 'nvme-6.15-2025-05-22' of git://git.infradead.org/nvme:
nvme: avoid creating multipath sysfs group under namespace path devices
