Pull cachefiles ondemand removal from Christian Brauner:
"This sunsets cachefiles ondemand mode.
It was an effort to make fscache usable as a kernel cache for lazy
pulling. EROFS over fscache was its only in-tree user. fscache has
since become netfslib-oriented while EROFS never acts as a network
filesystem and EROFS over fscache has been removed.
So this cleans up the netfs, fscache and cachefiles side as well"
* tag 'vfs-7.3-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
cachefiles,netfs: sunset ondemand mode
Pull kthread vfs updates from Christian Brauner:
"This stops kernel threads from sharing filesystem state with
userspace. This work is about 3 cycles old and has been in -next
for about that time.
When the kernel boots init_task creates PID 1 and then kthreadd. From
that point every kthread and PID 1 share the same fs_struct. That is
why pivot_root() has to rewrite the fs_struct of all kthreads. The
rewriting exists so that kthreads can use init's filesystem state when
they want to. It also means userspace can move the ground out from
under the kernel.
PID 1 now gets a completely separate fs_struct. All kthreads are
anchored in a private SB_KERNMOUNT instance of nullfs that cannot be
mounted on and cannot be used to follow other mounts. Userspace init
can no longer affect kthread filesystem state and kthreads can no
longer affect userspace fs state without explicit opting in to that.
Path lookup from a kthread now fails by default. It makes it
deliberately hard to offload security sensitive operations into init's
filesystem state from a kthread.
Places that legitimately need to look something up there opt in
through the new scoped_with_init_fs() which temporarily overrides the
caller's fs_struct with init's. usermodehelpers remain the only kernel
tasks that genuinely share init's filesystem state, since they execute
random binaries in the root filesystem (excellent...).
The visible result is that /proc/2/root is a nullfs with an empty
mountinfo while /proc/1/root is the real root"
* tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
initramfs_test: use test init/exit hooks to override init fs
fs: stop rewriting paths for PF_EXITING | PF_DUMPCORE
fs: stop rewriting kthread fs structs
fs: start all kthreads in nullfs
nullfs: make nullfs multi-instance
devtmpfs: create private mount namespace
fs: add umh argument to struct kernel_clone_args
fs: stop sharing fs_struct between init_task and pid 1
af_unix: use scoped_with_init_fs() for coredump socket lookup
initramfs: use scoped_with_init_fs() for rootfs unpacking
pnfs/blocklayout: use scoped_with_init_fs() for SCSI device lookup
ksmbd: use scoped_with_init_fs() for VFS path operations
ksmbd: use scoped_with_init_fs() for filesystem info path lookup
ksmbd: use scoped_with_init_fs() for share path resolution
fs: use scoped_with_init_fs() for kernel_read_file_from_path_initns()
coredump: use scoped_with_init_fs() for coredump path resolution
btrfs: use scoped_with_init_fs() for update_dev_time()
scsi: target: use scoped_with_init_fs() for APTPL metadata
scsi: target: use scoped_with_init_fs() for ALUA metadata
crypto: ccp: use scoped_with_init_fs() for SEV file access
...
Pull binfmt updates from Christian Brauner:
"This contains a bunch of work for binfmt_misc. It fixes a bunch of
old bugs, reworks the locking, and then extends the format registry
so a binary type can be matched programmatically and its interpreter
computed per exec instead of being a fixed string recorded at
registration time.
This allows nixos and other to e.g., implement relocatable binaries
meaning the interpreter/dynamic loader can be determined
programatically, say found relative to the binary. The mechanism is
flexible and can support other policies:
- Handler lookup is now an rcu walk. An exec that matches no
binfmt_misc entry should now never write to a shared cacheline
- remove the VERBOSE_STATUS and USE_DEBUG compile time toggles
- convert the entry file to a seq_file which simplifies things quite
a bit and kills a lot of custom logic
- make flags proper enums
- rename struct Node to binfmt_misc_entry
- allow entries to be removed with unlink(2)
- Add the ability to attach bpf programs to binfmt_misc entries so
it's possible to dynamically choose the execution environment such
as the loader or interpreter on a per binary basis.
A handler is an instance of a binfmt_misc_ops struct_ops with a
->match() and a ->load() program. match() decides from the entry
lookup walk whether the handler applies under the same
registration-order. It can read file content as needed not only the
prefetched 256 bytes in bprm->buf.
load() then selects the interpreter and stages it through the new
bpf_binprm_set_interp(), bpf_binprm_set_interp_arg() and
bpf_binprm_set_flags() kfuncs.
Handlers are published in a registry keyed by the registering
task's user namespace and activated through the existing text
interface with a new 'B' type carrying the handler name:
echo ':origin:B::::nix:' > /proc/sys/fs/binfmt_misc/register
The permission and namespacing model is unchanged. Activating a
handler requires the same write access to an instance as any other
registration. A container mounting its own instance escapes the
host's entries exactly as before. The computed interpreter is
opened with open_exec() under the caller's credentials and goes
through full LSM vetting as the next binprm level. A program can
only ever redirect the caller to something the caller could exec
anyway.
- Two dispatch modes are added. So far the chosen interpreter owns
the whole process identity (argv[0], /proc/pid/cmdline,
/proc/self/exe all name interpreter information). So relocatable
find the dynamic linker instead. Also a binary passed to execveat()
as an inaccessible O_CLOEXEC fd cannot run at all and gdb trips
because AT_ENTRY and AT_PHDR do not match the exe file. So PIE
symbols are unrelocated.
This adds transparent dispatch which allows the interpreter to load
the binary through AT_EXECFD and leaves the argument vector exactly
as the caller built it and labels mm->exe_file and comm with the
binary. It also raises the AT_FLAGS_TRANSPARENT_INTERP aux vector
bit. The interpreter keeps control of mapping the binary.
The second mode is loader substitution. This allows a binary to be
executed natively and only the interpreter to be changed.
- Last, interpreters can be bound at registration time. Each
interpreter is opened by its own write with the credentials the
entry file was opened with. The program picks one per exec with
bpf_binprm_select_interp().
Ucounts are used to properly account for pre-opened interpreters
via /proc/sys/user/max_binfmt_misc_interpreters"
* tag 'vfs-7.3-rc1.binfmt' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (63 commits)
binfmt_misc: document the pre-opened interpreter limit
selftests/exec: test the pre-opened interpreter limit
binfmt_misc: correctly account pre-opened interpreters
binfmt_misc: document interpreters bound by a 'B' entry
selftests/exec: test interpreters bound to a 'B' entry
binfmt_misc: let a 'B' entry bind its interpreters
binfmt_misc: carry pre-opened interpreters in struct binfmt_misc_interp
selftests/exec: share the bpf handler preconditions
binfmt_misc: document registering an entry disabled
selftests/exec: test registering an entry disabled
selftests/exec: let binfmt_flag_supported() return a bool
selftests/exec: check that a binfmt_misc instance cannot be pinned
binfmt_misc: let a register string create an entry disabled
binfmt_misc: document loader substitution
selftests/exec: test binfmt_misc loader substitution
binfmt_misc: let a bpf handler request loader substitution
binfmt_misc: add the 'L' loader substitution flag
binfmt_elf_fdpic: consume a stashed PT_INTERP substitute
binfmt_elf: consume a stashed PT_INTERP substitute
exec: carry a PT_INTERP substitute in struct linux_binprm
...
Pull misc ipc and core updates from Christian Brauner:
- reject mq_notify() with a zero signal number
- fix coding style in the exit path
* tag 'ipc-7.3-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
mqueue: reject mq_notify with signo 0
* tag 'kernel-7.3-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
kernel: exit: fix coding style missing spaces
Pull scheduler fix from Borislav Petkov:
- Make sure a delayed sched entity's runtime stats are updated at the
right time so that it receives the proper lag compensation
* tag 'sched_urgent_for_v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Update time before requeueing delayed entities
Pull perf fixes from Borislav Petkov:
- Prevent the use of exited events as group leaders
- Avoid use-after-free of an event's group leader by promoting detached
sibling events to standalone entities and correct related accounting
and state transitions
* tag 'perf_urgent_for_v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix group leader use-after-free after sibling detach
perf: Reject exited events as group leaders
Pull vfs fixes from Christian Brauner:
- Don't warn when a mount is completed from another user namespace.
fsopen() records the caller's user namespace in fc->user_ns and
hands back an ordinary file descriptor. The task that calls
fsconfig(FSCONFIG_CMD_CREATE) doesn't have to be the one that
created the context, and mount_capable() lets it through as long
as the caller has CAP_SYS_ADMIN over fc->user_ns, which anyone in
an ancestor namespace does. So fc->user_ns != current_user_ns()
is something an unprivileged user can arrange.
Both overlayfs and binfmt_misc WARN_ON() that. Overlayfs already
has the same check as a plain error return in ovl_parse_param().
Drop the WARN_ON() and just refuse. Add selftests for both cases.
- Reject pid allocations through dead ancestor pid namespaces.
Require PIDNS_ADDING in every namespace that will receive the pid
before publishing any of them. That preserves the invariant that
free_pid() never decrements pid_allocated in a namespace whose
child_reaper is no longer live. The existing ENOMEM behavior is
unchanged.
* tag 'vfs-7.2-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
pid: reject allocations through dead ancestor pid namespaces
selftests/filesystems: test completing a context from another user namespace
binfmt_misc: don't warn when the mount is completed from another user namespace
ovl: don't warn when the mount is completed from another user namespace
In order to compute the right lag, it is required to update time to 'now'.
Without this, the delayed entity might appear younger than it really is and
receive less compensation for having waited.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
The following sequence may leads race between event_define_fields()
and update_event_fields():
CPU0 (loads module A) CPU1 (loads module B)
=============================== ===============================
load_module(A) load_module(B)
notifier_call_chain notifier_call_chain
trace_module_notify trace_module_notify
mutex_lock(&event_mutex) trace_event_update_all()
trace_module_add_events(A) down_write(&trace_event_sem)
__register_event(call_A)
__add_event_to_tracers(call_A)
event_define_fields(call_A)
for each f: list_for_each_entry(field,
list_add(&f->link, &class->fields, link)
&class->fields) field = class->fields->next;
Where access to the class->fields is not protected by the event_mutex in
trace_event_update_all().
This produces the following panic:
Unable to handle kernel access ... at virtual address 0000000000000018
pc : update_event_fields+0xf8/0x368
Call trace:
update_event_fields+0xf8/0x368
trace_event_update_all+0x7c/0x2b4
trace_module_notify+0x4c/0x1dc
notifier_call_chain+0x84/0x168
blocking_notifier_call_chain_robust+0x64/0xd4
load_module+0x10c8/0x123c
__arm64_sys_finit_module+0x230/0x31c
Fix by taking event_mutex in trace_event_update_all() before
trace_event_sem.
Cc: stable@vger.kernel.org
Fixes: b3bc8547d3 ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well")
Link: https://patch.msgid.link/2e5730d2-c631-da41-3a3a-ae35bb4895f3@allwinnertech.com
Signed-off-by: Michael Wu <michael@allwinnertech.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A module-only event filter such as ":mod:foo" is cached with a NULL
event_mod->match when foo has not been loaded. If a later write tries to
remove a specific match from the same module, remove_cache_mod() passes
the NULL cached match to strcmp(), causing a NULL pointer dereference.
The issue can be reproduced from userspace:
echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event
echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event
The second write must be a concatenation (">>") to not include O_TRUNC as
that would cause ftrace_clear_events() to clear the cached modules lines.
The crash was reproduced on x86_64 QEMU while KUnit workers contended on
the event tracing path:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
RIP: 0010:strcmp+0x10/0x30
Call Trace:
__ftrace_set_clr_event_nolock+0x373/0x4a0
ftrace_set_clr_event+0xf0/0x180
ftrace_event_write+0xdf/0x110
vfs_write+0xf6/0x440
ksys_write+0x68/0xe0
do_syscall_64+0xf9/0x540
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Check event_mod->match before comparing it, consistent with the existing
NULL checks for the cached system and event fields. The mismatched removal
continues to return -EINVAL; a broad cached module filter is removed with
"!:mod:<module>".
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260811173902.1927376-2-sh_def@163.com
Fixes: b355247df1 ("tracing: Cache \":mod:\" events for modules not loaded yet")
Reported-by: syzbot+4d3143c8e28f6266c636@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/6a7a6b7f.9c11d2ce.289b96.00f8.GAE@google.com/
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
alloc_pid() checks PIDNS_ADDING only on the leaf pid namespace before
making a new struct pid visible in every ancestor namespace. That is
insufficient when an unborn descendant pid namespace outlives an
ancestor whose init task has already exited. The descendant can still be
initialized later through setns(), and the new pid is then published
into the dead ancestor as well.
Keep the existing ENOMEM behavior, but require PIDNS_ADDING to be set in
every namespace that will receive the new pid before publishing any of
them. This preserves the invariant that free_pid() never decrements
pid_allocated in a namespace whose child_reaper is no longer live.
Fixes: a3bdc23ba8 ("pid_namespace: allow opening pid_for_children before init was created")
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Pull tracing fixes from Steven Rostedt:
- Fix use-after-free in eventfs_remove_rec()
The freeing of the eventfs_inode children used list_for_each_entry()
where the child is freed via srcu, but there's still a chance that it
gets freed. It should be using list_for_each_entry_safe().
- Fix eventfs_inode SRCU use of list in freeing
The iterator uses an SRCU protected list walk on the eventfs inodes.
The eventfs inode uses its "list" field in a union with the RCU list
head. When the inode gets added to the SRCU list it immediately
corrupts the list pointer and can cause an issue with the iterator.
Move the RCU list head to be shared with the children list head which
allows the iterator to check the parent inode if is freed before
referencing the child. Have the iterator check the parent "is_freed"
field and break out if it is set. Also add memory barriers to make
sure the ordering is correct.
- Fix various RCU synchronization issues with direct_functions
Updates to direct_functions have some missing RCU protection and
synchronization. Restructure the code a bit to make sure updates to
the direct_functions are protected.
- Remove an unneeded comma from a scope_guard()
There's a spurious comma in a scope_guard(). Remove it.
- Fix race in per CPU buffer swap in the ring buffer
When a per CPU buffer swap happens, it must make sure that it doesn't
occur while a writer is active. Instead it returns an -EBUSY. But
there's a small race window when a writer moves from one sub-buffer
to the next that it resets the "committing" counter. If a swap
happens at that moment, the buffer used for the commit of an event
will not match the buffer the event is actually on. Instead of using
the "committing" counter, use the recursive detection counter that
does not get reset when the writer crosses sub-buffers.
- Fix off-by-one in ftrace_free_mem()
The function ftrace_free_mem() gets an "end_ptr" as a parameter that
is exclusive to the rang to be freed. But its value is used to search
for the records that expects an inclusive value. Subtract one from
the parameter to convert it to an inclusive range.
- Disable resizing of the ring buffer for persistent buffers
Resizing the persistent buffer has undefined behavior. Prevent it
from being resized.
- Disable changing ring buffer subbuf order when resizing is disabled
The ring buffer subbuffer order can not be changed during resizing.
Use that instead of just checking if the buffer is mapped as mapped
buffers also have resizing disabled.
- Initialize subbuf_order of reader pages when they are created
In rb_allocate_cpu_buffer() the bpage->order is not updated to the
current subbuf_order leaving it as zero. This value is used when the
page is freed.
- Fix test_ringbuffer() to test for ERR_PTR before calling
kthread_stop()
The rb_threads[] array is assigned the output of kthread_run_on_cpu()
which could return an ERR_PTR. At the end of the test, all threads in
the array are cleaned up by kthread_stop() passing in the value in
the array if it isn't zero. But if the array contains an ERR_PTR,
kthread_stop() will not be able to handle it properly.
* tag 'trace-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
ring-buffer: Initialise reader page order in rb_allocate_cpu_buffer()
ring-buffer: Prevent subbuf order change when resizing is disabled
ring-buffer: Prevent resizing of persistent ring buffer
ftrace: Fix off-by-one fentry site disable in ftrace_free_mem()
ring-buffer: Use current_context for safe per-CPU buffer swap
ftrace: Drop extra comma in trace_buffered_event_enable
ftrace: Protect direct_functions in update_ftrace_direct_mod
ftrace: Protect direct_functions in update_ftrace_direct_del
ftrace: Protect direct_functions in ftrace_find_rec_direct
eventfs: Use children field for rcu head and add memory barriers
eventfs: Fix use-after-free in eventfs_remove_rec()
In test_ringbuffer()'s out_free cleanup loop, the check
`!rb_threads[cpu]` only catches NULL entries and misses entries that
hold an ERR_PTR.
rb_threads[] is static, so unassigned slots are NULL. But when
kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or
-EINTR) in rb_threads[cpu] before the creation loop jumps to out_free.
That entry is non-NULL, so the old `!ptr` check does not break, and the
cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop()
then dereferences the bogus pointer, crashing the kernel during the
late_initcall self-test.
crash logs:
BUG: kernel NULL pointer dereference, address: 000000000000001c
Oops: 0002 [#1] SMP NOPTI
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy)
RIP: 0010:kthread_stop+0x2e/0x220
RBX: fffffffffffffff4
CR2: 000000000000001c
Call Trace:
<TASK>
test_ringbuffer+0x1ec/0x650
do_one_initcall+0x6c/0x2c0
kernel_init_freeable+0x21d/0x420
kernel_init+0x15/0x1c0
ret_from_fork+0x21b/0x320
</TASK>
Kernel panic - not syncing: Fatal exception
Cc: stable@vger.kernel.org
Fixes: 64ed3a049e ("ring-buffer: make use of the helper function kthread_run_on_cpu()")
Link: https://patch.msgid.link/20260807154145.2846521-2-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When a module's init text is freed, do_init_module() calls
ftrace_free_mem() with a half-open [start, end) range. However the
ftrace_cmp_recs() comparator treats the upper bound as inclusive, as all
its other users do, passing 'ip + size - 1'. So ftrace_free_mem() can
delete a record sitting exactly at 'end', which is outside the freed
range.
For a kernel without CFI or IBT, the first record of a function is at
the function start, which for the first function in a module is also the
base of its text allocation. As the module allocator packs its regions,
that address is often the 'end' passed by a neighboring module's
do_init_module(), causing the first function's ftrace location to get
disabled, preventing an attempt to livepatch it:
livepatch: failed to find location for function 'pcspkr_probe'
Convert the exclusive end to the inclusive 'end - 1' the comparator
expects, and return early for an empty range to avoid the subtraction
from underflowing when the init text size is zero.
Cc: stable@vger.kernel.org
Fixes: 42c269c88d ("ftrace: Allow for function tracing to record init functions on boot up")
Link: https://patch.msgid.link/1b5ccfa8095bdb1277f84af1c2c2e2205aca03ae.1785992188.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:
ring_buffer_lock_reserve
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_a
rb_reserve_next_event
rb_start_commit // inc committing
if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
__rb_reserve_next
rb_move_tail
rb_end_commit(cpu_buffer); // dec committing => 0
/* interrupt hits here, successfully swaps! */
local_inc(&cpu_buffer->committing);
ring_buffer_unlock_commit
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_b
rb_commit
rb_end_commit
RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
// triggers warning
The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().
Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.
Cc: stable@vger.kernel.org
Fixes: 4239c38fe0 ("ring-buffer: Process commits whenever moving to a new page.")
Link: https://patch.msgid.link/20260803005640.2445666-2-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull futex fix from Ingo Molnar:
- Fix race in futex_pivot_pending() during private hash resize
that can cause stuck tasks (Yao Kai)
* tag 'locking-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Fix race in futex_pivot_pending() during private hash resize
perf_group_detach() handles leader and sibling detach differently. When the
group leader is detached, all siblings are promoted to singleton events and
their group_leader pointer is reset to themselves. When a sibling is
detached, it is removed from the leader's sibling_list, but its
group_leader pointer is left pointing at the old leader.
That is harmless when the sibling is being closed and freed immediately, as
in the DETACH_DEAD path. It is not safe when the sibling is detached but
kept alive, such as during CPU hotplug with DETACH_GROUP. In that case the
sibling is removed from the context, while its file descriptor can still
keep it alive.
A typical failing sequence is:
- A group contains leader L and sibling S.
- CPU hot-unplug detaches S with DETACH_GROUP, removing it from
L->sibling_list but leaving S->group_leader == L.
- L is later closed and freed.
- A PERF_IOC_FLAG_GROUP ioctl on S follows S->group_leader and
dereferences the freed leader.
This was reproduced by running the perf event fuzzer, CPU hotplug, and a
stress workload concurrently:
Unable to handle kernel paging request at virtual address 006b6b6b6b6b6cdb
CPU: 2 PID: 12489 Comm: perf_fuzzer 6.18.7 PREEMPT
pc : perf_ioctl+0x34c/0xc68
x20: ffffff89a3fa2c70 x8 : 6b6b6b6b6b6b6b6b
Code: 943c4a0e 340047a0 f9404a94 f9411e88 (f940b908)
Call trace:
perf_ioctl+0x34c/0xc68 (P)
__arm64_sys_ioctl+0xa0/0xf4
invoke_syscall+0x58/0xe4
el0_svc_common+0xa8/0xdc
do_el0_svc+0x1c/0x28
el0_svc+0x40/0xc0
el0t_64_sync_handler+0x68/0xdc
el0t_64_sync+0x1c4/0x1c8
The fault happened in perf_ioctl(), where perf_event_for_each() follows
the stale group_leader pointer and perf_event_for_each_child() then
dereferences the freed leader's context.
Fix the use-after-free by promoting the detached sibling to a singleton.
Also fix __event_disable() cgroup accounting and event state change.
Fixes: 8a49542c05 ("perf_events: Fix races in group composition")
Assisted-by: PatchWise:gpt-5.5
Signed-off-by: Aditya Chillara <aditya.chillara@oss.qualcomm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260807-fix-group-leader-uaf-v3-1-b0c2310c9a0d@oss.qualcomm.com
perf_event_remove_on_exec() sets remove-on-exec events to the EXIT state
and detaches their group relationships. The event's file descriptor can
remain open, however, and perf_event_open() currently accepts that event
as a group leader because its early validation rejects only REVOKED and
DEAD events.
A new sibling can consequently be linked to the detached leader. When
the leader is closed, perf_group_detach() observes that its
PERF_ATTACH_GROUP bit is already clear and skips the new sibling. The
sibling then retains a group_leader pointer to the freed event.
Reject group leaders in the EXIT state. Perform the check while holding
the shared context mutex so that an exec in the target task cannot detach
the leader between validation and group attachment.
[peterz: make the earlier test fully consistent]
Fixes: 037a3c43ed ("perf/core: Detach event groups during remove_on_exec")
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260806205655.75722-1-kylebot@openai.com
A task performing a custom private hash resize can remain blocked in
uninterruptible sleep indefinitely. The hung-task detector reports:
INFO: task futex-resizer:314 blocked for more than 10 seconds.
task:futex-resizer state:D stack:14824 pid:314 tgid:312 ppid:311
Call Trace:
__schedule+0x521/0xf30
schedule+0x22/0xa0
futex_hash_allocate+0x3db/0x490
__do_sys_prctl+0x6f5/0xbd0
do_syscall_64+0xf9/0x530
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Kernel panic - not syncing: hung_task: blocked tasks
futex_pivot_pending() allows the resize request to continue when
either no replacement hash is pending (hash_new == NULL) or the current
hash reference count has reached zero.
After the final-reference wake, another futex task can complete the
pivot between the two observations:
T1 T2
futex_hash_allocate()
wait_var_event(mm, ...)
futex_pivot_pending(mm)
hash_new != NULL
futex_hash()
futex_ref_get(old) -> false
futex_pivot_hash(mm)
hash_new = NULL
__futex_pivot_hash(mm, new)
rcu_assign_pointer(hash, new)
fph = rcu_dereference(hash) /* new */
futex_ref_is_dead(fph) -> false
schedule()
The pivot changes the state from hash_new != NULL with a dead current
hash to hash_new == NULL with a live current hash. Because
futex_pivot_pending() reads hash_new and hash without serialization,
the resize task can observe hash_new in the pre-pivot state and hash in
the post-pivot state, causing futex_pivot_pending() to return false even
though the pivot has completed. The task then goes to sleep after the
wakeup has already been consumed.
Serialize state reads in futex_pivot_pending() using futex_mm_phash::lock.
This guarantees that futex_pivot_pending() observes hash_new and hash
atomically, eliminating the race condition.
Fixes: bd54df5ea7 ("futex: Allow to resize the private local hash")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Yao Kai <yaokai34@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260804125530.3933754-1-yaokai34@huawei.com
Pull BPF fixes from Daniel Borkmann:
- Fix BPF verifier to preserve full pointer state for commuted
scalar += pointer arithmetic (Yiyang Chen, Eduard Zingerman)
- Fix a use-after-free of request sockets in the BPF TCP iterator
batching (Jose Fernandez)
- Fix a use-after-free of sk_redir in the BPF sockmap send verdict
path (Chengfeng Ye)
- Fix a netns reference imbalance in the BPF conntrack kfuncs
(Chengfeng Ye)
- Fix bpf_get_fsverity_digest() dynptr assumptions and silent
digest truncation (Eric Biggers)
- Fix bpf_tcp_{gen,check}_syncookie to check sk_state before
sk_protocol to make sure it is a full socket (Luxiao Xu)
- Fix rqspinlock to reset the tail when preserving the queue
on deadlock (Kumar Kartikeya Dwivedi)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
rqspinlock: Reset tail when preserving queue on deadlock
bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie
fsverity: Fix silent truncation in bpf_get_fsverity_digest()
fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions
bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()
bpf: Fix netns reference imbalance in conntrack kfuncs
bpf, sockmap: Fix sk_redir use-after-free in send verdict
selftests/bpf: Cover commuted pointer state propagation
bpf: Propagate untrusted pointer state in commuted arithmetic
bpf: Preserve pointer state for commuted arithmetic
bpf: Simplify sanitize_err() signature
Currently, the destruction of the waiter queue is suppressed for
rqspinlock in cases where a deadlock is detected. Deadlock checks happen
relatively frequently (on entry for AA, within 1ms for ABBA), and waiter
threads may not be involved in locking scenarios involving deadlocks.
Thus, it is useful to not flush the queue and let other waiters take a
stab at acquiring the lock after we detect a deadlock and exit.
However, we need to follow the same logic as what we did previously for
the waitq_timeout label: reset the tail, and if we cannot, signal the
next waiter appropriately. In case of deadlocks, this signal would just
mark the MCS node as unlocked, and in case of timeouts, it would signal
RES_TIMEOUT_VAL. The difference thus is in the value propagated, which
decides whether the queue remains active or gets flushed.
Not doing the tail reset, and waiting for the next waiter can lead to
cases where we are the final waiter, and thus no next waiter arrives,
leading to intermittent stalls in this path. Once the next waiter does
join, we will be unblocked. In the theoretical case when the next waiter
never joins, we risk stalling indefinitely.
This can only happen for ABBA deadlocks, since entry into the wait queue
is guarded with AA checks. A precise sequence of executions leading up
to this scenario can be:
CPU 0 holds lock A.
CPU 1 holds lock B.
CPU 2 attempts lock B, becomes the pending waiter for B.
CPU 0 attempts lock B. B has locked+pending bits set, thus CPU 0 queues.
CPU 1 attempts lock A.
CPU 0 detects an ABBA deadlock.
Once deadlock detection happens for CPU 0, it will sit waiting for the
next waiter in the queue to populate node->next, which will experience
delays until such a waiter arrives.
Fix this by adjusting the logic for the check for deadlocks preceding
the waitq_timeout label. It would make sense to consolidate code for
both cases and use 'ret' to distinguish the value being propagated, but
that is left as an exercise for a future refactoring task to avoid diff
noise in this patch.
Fixes: 7bd6e5ce5b ("rqspinlock: Disable queue destruction for deadlocks")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://patch.msgid.link/20260802021759.1139457-1-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Pull futex fix from Ingo Molnar:
- Fix a robust futexes exit race (Keno Fischer)
* tag 'locking-urgent-2026-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Prevent robust futex exit race some more
An 'F' entry, and every interpreter a 'B' entry binds, holds a file open
from registration until the entry goes away, pinning the file, its inode,
the mount it came from and that mount's superblock. Nothing bounds how
many of those a user namespace can hold. An entry binds at most
BINFMT_MISC_INTERP_MAX interpreters, but nothing caps the entries.
Charge each binding to the user namespace and uid that makes it against a
new UCOUNT_BINFMT_MISC_INTERPRETERS. Going over budget causes -ENOSPC.
A per-instance cap would suck. Instances are keyed on the user
namespace. So any constant is multiplied by the number of namespaces the
caller creates. Creating those is virtually free. A ucount charges the
namespace and every one of its ancestors. And a namespace can raise only
its own limit. So nesting buys nothing.
The knob is /proc/sys/user/max_binfmt_misc_interpreters. Leave it at the
max_threads/2 default fork_init() gives a new type. No existing
configuration comes close to that.
binfmt_misc is tristate, which makes it the first ucount user that can be
built as a module. Export inc_ucount() and dec_ucount(); without them
CONFIG_BINFMT_MISC=m fails to link. Export them to binfmt_misc alone:
charging a ucount type is not something a module has any business doing
in general, and the list is trivial to extend if a second user shows up.
init_user_ns and init_binfmt_misc are already exported for the same
module.
Link: https://patch.msgid.link/20260803-work-binfmt_misc-interplimit-v1-1-4a2435500bd9@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Pull liveupdate fix from Mike Rapoport:
- fix a regression caused by allowing coexistence of KHO with deferred
initialization of the memory map
* tag 'liveupdate-fixes-2026-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux:
kho: align kho_scratch to MAX_ORDER_NR_PAGES pages
Pull sched_ext fixes from Tejun Heo:
- More lifecycle fixes for the new sub-scheduler support: a failed
enable could tear down a never-linked sub-scheduler in a way that
races the root scheduler's disable and leads to a use-after-free,
tasks that were not on the ext class could still get the enable
callback, and a policy-rejection path silently rewrote a running
task's scheduling policy instead of aborting the scheduler.
- Scheduler enable/disable could deadlock with cgroup removal and a
concurrent cgroup weight write through kernfs. Fixed by reordering
lock acquisition.
- Sync wakeups could leave the waker CPU incorrectly marked idle in the
built-in idle-CPU tracking.
- A selftest fix for sleeping tasks whose CPU affinity changes before
wakeup.
* tag 'sched_ext-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
selftests/sched_ext: Handle sleeping task affinity changes in numa test
sched_ext: Mark waker CPU busy when selected in WAKE_SYNC case
sched_ext: Don't enable non-ext tasks in the sub-sched task loops
sched_ext: Skip sub-disable teardown for never-linked sub-schedulers
sched_ext: Take cgroup_lock() first in scx_cgroup_lock()
sched_ext: Reject setting disallow from init_task outside the enable path
Pull cgroup fixes from Tejun Heo:
- A pressure trigger's poll timer could be re-armed while the last
trigger was being torn down and then fire after the cgroup was freed.
Tie the timer to the cgroup's lifetime and shut it down when the
cgroup is freed.
- Writing to a pressure file forked a worker kthread while holding the
cgroup mutex, creating lock dependencies from the mutex to the whole
fork path. A pressure write racing a sched_ext scheduler enable,
which blocks forks before grabbing the mutex, deadlocked.
Fork the worker with the mutex dropped.
- Documentation fix for io.latency behavior on non-rotational devices.
* tag 'cgroup-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Docs/admin-guide/cgroup-v2: document io.latency rotational vs non-rotational behavior
sched/psi: Shut down rtpoll_timer in psi_cgroup_free()
sched/psi: Create the psimon kthread outside of cgroup_mutex
Once binfmt_misc is loaded load_misc_binary() runs for every execve()
on the system since binfmt_misc registers at the head of the formats
list. Every exec therefore performs read_lock() and read_unlock() on
the entries_lock of the relevant binfmt_misc instance, i.e., two
atomic read-modify-writes on a shared cacheline. User namespaces
without their own binfmt_misc mount fall back to an ancestor's
instance so on container-heavy systems every exec on the machine
typically ends up hammering the cacheline of init_binfmt_misc. On
PREEMPT_RT the rwlock additionally turns the handler lookup into a
sleeping lock on the exec fast path.
The lock protects very little. Entries are immutable after publication
except for the Enabled bit which is already toggled locklessly via
set_bit()/clear_bit() and entry lifetime is already handled by the
users refcount via get_binfmt_handler()/put_binfmt_handler(). The read
lock's only remaining job is to make "the entry is still linked" and
"take a reference" atomic with respect to the unlink sites.
Switch the lookup to an RCU walk:
* Lookup walks the entry list under rcu_read_lock() and acquires a
reference via refcount_inc_not_zero(). The refcount can only drop to
zero after an entry has been unlinked so a failed increment means
the walk raced with an unlink. Restarting the search is bounded
because an unlinked entry cannot be found again.
* The unlink sites use hlist_del_init_rcu() which keeps the forward
pointer intact for concurrent walkers and preserves hlist_unhashed()
as the protection against double removal.
* The final put frees the entry via kfree_rcu() as a concurrent walker
may still dereference its flags, magic, mask, and inline strings.
They all live in the entry allocation itself and thus stay valid
until a grace period has elapsed. Closing the interpreter file stays
synchronous. It is only used with a reference already held and all
final puts run in process context.
* Writers remain serialized by the inode lock of the root dentry with
one exception. bm_evict_inode() called from generic_shutdown_super()
during umount unlinks entries without holding it. Keep a spinlock
around the unlink sites instead of relying on superblock lifetime
rules to make that exclusion implicit.
Handler removal semantics are unchanged. An exec that acquired a
reference just before its handler was unregistered already completes
with the removed handler today. The read lock never protected against
that, it only made the window smaller.
With this an exec that matches no binfmt_misc entry, the common case,
no longer writes to any shared cacheline at all.
Link: https://patch.msgid.link/20260710-work-binfmt_misc-locking-v3-5-a162f7cb58d6@kernel.org
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
The upcoming conversion of the handler lookup to RCU walks cannot use
list_del_init(): reinitializing the forward pointer of a removed entry
would make a concurrent lockless walker standing on that entry loop
back onto it indefinitely. The removal paths do rely on
reinitialization though because bm_{entry,status}_write() and
bm_evict_inode() need to detect whether an entry has already been
unlinked.
hlists support exactly this pattern: hlist_del_init_rcu() keeps the
forward pointer of the removed entry intact for concurrent walkers and
only zeroes ->pprev with hlist_unhashed() serving as the linked test.
Convert the entry list to an hlist now while keeping the rwlock so the
subsequent RCU conversion is a pure locking change. hlist_add_head()
inserts at the head just as list_add() did so lookup precedence
between registered handlers is unchanged.
Link: https://patch.msgid.link/20260710-work-binfmt_misc-locking-v3-4-a162f7cb58d6@kernel.org
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Pull scheduler fix from Ingo Molnar:
- Fix wakeups of deferred DL servers to be actually deferred (Gabriele
Monaco)
* tag 'sched-urgent-2026-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Use revised wakeup rule only for running dl_server
Pull uprobes fix from Ingo Molnar:
- Fix uretprobes race that can crash the kernel (Breno Leitao)
* tag 'perf-urgent-2026-08-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
uprobes: Fix NULL pointer dereference in hprobe_expire()
A robust futex unlock stores 0 over the whole futex value - wiping
FUTEX_WAITERS - and wakes a single waiter. That wakeup is a one-shot
notification: the protocol relies on its recipient to either acquire the
futex (and eventually unlock while aware of the remaining contention) or
re-arm FUTEX_WAITERS before sleeping again. If the woken waiter is killed
before it can do either, the kernel must jump in and wake the next task
down the line.
This is a known complication of the futex protocol with a previous
partial fix in commit ca16d5bee5 ("futex: Prevent robust futex exit
race"). Unfortunately, that fix is insufficient.
If a third task re-acquired the futex through the uncontended fast
path in the meantime, the notification is lost: robust exit processing
sees that it is owned by another task and does nothing, while the new
owner sees no FUTEX_WAITERS when it unlocks and wakes nobody.
The remaining waiters sleep forever behind a free futex:
A owns the futex, B and C sleep in FUTEX_WAIT
uval == A | FUTEX_WAITERS
A robust unlock: store 0, FUTEX_WAKE(1) wakes B
uval == 0
D fast path acquire: cmpxchg(0 -> D)
uval == D, no FUTEX_WAITERS
B killed before acting on the wakeup
B exit walk, pending op: owner D != B -> no action
D unlock: no FUTEX_WAITERS -> no wake
C sleeps forever
This is clearly a shortcoming in the implementation, which fails to keep
the FUTEX_WAITERS bit consistent.
Work around this by augmenting the robust list exit processing to also
perform the extra wakeup if the futex word is owned by another thread but
FUTEX_WAITERS is not set.
This does not fix the problem of a non-contended take over/release and free
sequence, which has been discussed for years and has been addressed by
commit 3ca9595d9f ("futex: Add support for unlocking robust futexes") and
subsequent changes, but failed to take the problem described above into
account.
A more complete solution which is based on the in kernel unlock of
contended robust futexes has been discussed in the context of this change
and should show up in mainline sooner than later.
[ tglx: Amend change log slightly and fixup coding style ]
Fixes: ca16d5bee5 ("futex: Prevent robust futex exit race")
Signed-off-by: Keno Fischer <keno@juliahub.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Assisted-by: ClaudeCode:claude-fable-5 tla+
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730194705.38981-1-keno@juliacomputing.com
Pull tracing fixes from Steven Rostedt:
- Reset dropped_count in mmio_reset_data()
When mmio_reset_data() is called, it does not reset the dropped_count
so that subsequent runs will have incorrect reporting.
- Add NULL check for mmio_trace_array in logging functions
The functions __trace_mmiotrace_rw() and __trace_mmiotrace_map() may
have the 'tr' variable passed to it as NULL. But they both
dereference it without checking if it is NULL first.
- Check return value of __register_event() in trace_module_add_events()
If __register_event() fails, the __add_event_to_tracers() call after
it will create a file for it. If the module fails to load and its
memory is freed, the file will still point to it and it will not be
removed as the registering of the event did not complete.
Only call __add_event_to_tracers() if the __register_event() was
successful.
- Fix false positive match in regex_match_full()
The regex full matching uses a strncmp() to test against the match
string and the value. It should not match if value is a prefix of the
string to match. Check to make sure the length of the strings match
before comparing.
- Fix reader page read offset for remote buffers
A page swapped in by __rb_get_reader_page_from_remote() retains its
stale read offset, causing subsequent reads to skip events or read
past valid data.
- Fix memory leak of subbuf_ids in rb_allocate_cpu_buffer()
Remote buffers allocate a subbuf_ids array. If the allocator function
fails after it is allocated, it does not free it, resulting in a
memory leak.
* tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
ring-buffer: Fix reader page read offset for remote buffers
tracing/filters: Fix false positive match in regex_match_full()
tracing: Check return value of __register_event() in trace_module_add_events()
tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
In rb_allocate_cpu_buffer(), cpu_buffer->subbuf_ids is allocated using
kcalloc() when buffer->remote is non-NULL. If a subsequent page allocation
fails (e.g., ring_buffer_desc_page() returns NULL or rb_allocate_pages()
fails), execution jumps to fail_free_reader.
While __free(kfree) automatically frees the outer cpu_buffer structure
at scope exit, kfree(cpu_buffer) does not recursively free nested heap
pointers such as cpu_buffer->subbuf_ids, resulting in a memory leak.
Fix this by explicitly freeing cpu_buffer->subbuf_ids in the
fail_free_reader error unwinding path when cpu_buffer->remote is set.
Link: https://patch.msgid.link/178550740672.380917.6067449683620196150.stgit@devnote2
Fixes: 2e67fabd8b ("ring-buffer: Introduce ring-buffer remotes")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When scalar += pointer is handled in adjust_ptr_min_max_vals(), the
destination register inherits the pointer state from the source pointer.
Copying only selected fields is fragile because pointer provenance is
tracked by several bpf_reg_state fields.
Use the caller's temporary offset register to preserve the scalar operand
while replacing the destination with the full pointer state. This preserves
the frame number for PTR_TO_STACK registers and keeps parent identity
fields consistent.
Fixes: f4d7e40a5b ("bpf: introduce function calls (verification)")
Signed-off-by: Yiyang Chen <chenyy23@mails.tsinghua.edu.cn>
Tested-by: Daniel Wade <danjwade95@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://patch.msgid.link/20260729-c3-035-public-bpf-v4-v4-2-8ee297e2346b@mails.tsinghua.edu.cn
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Forking a task that has a pending uretprobe can oops the kernel with a
NULL pointer dereference in the clone() path:
BUG: kernel NULL pointer dereference, address: 0000000000000018
Oops: 0002 [#1] SMP NOPTI
RIP: 0010:hprobe_expire
CR2: 0000000000000018
Call Trace:
uprobe_copy_process
copy_process
kernel_clone
__x64_sys_clone
do_syscall_64
entry_SYSCALL_64_after_hwframe
This was found on real hosts on Meta fleet.
I've got the impression that this is what is happening:
CPU 1 CPU 2 (traced task)
----- -------------------
hit uprobe, prepare_uretprobe():
hprobe LEASED, refcount >= 1
uprobe_unregister()
put_uprobe(): refcount -> 0
fork() -> dup_utask()
hprobe_expire(hprobe, true)
try_get_uprobe() -> NULL
get_uprobe(NULL) <-- Oops
Only take the extra reference when the uprobe is non-NULL; a NULL means
it is gone and is the correct value to return.
Fixes: dd1a756778 ("uprobes: SRCU-protect uretprobe lifetime (with timeout)")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260729-uprobe-v1-1-61896b87c867@debian.org
Pull audit fixes from Paul Moore:
- Fix potential integer overflows in audit_log_n_string()
Similar to the earlier fix to audit_log_n_hex() that you merged
earlier in July. Expect a cleaner, and generally better fix for these
functions in an upcoming merge window, but this addresses the problem
in a small patch that should be easy for people to backport.
- Fix potential use-after-free in audit_del_rule()
* tag 'audit-pr-20260730' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: fix potential use-after-free in audit_del_rule()
audit: fix potential integer overflow in audit_log_n_string()
Pull power management fixes from Rafael Wysocki:
"These fix issues related to cpufreq, in the ACPI CPPC library and the
generic CPPC cpufreq driver, in the powernow-k8 and amd-pstate
drivers, and in the schedutil governor:
- Allow fast frequency switching in the ACPI CPPC library only when
every supported control used by the driver callback has an address
space already accepted for fast access (Christian Loehle)
- Skip writes to unsupported performance controls in the ACPI CPPC
library (Christian Loehle)
- Update cppc_cpufreq_update_perf_limits() to read policy->min and
policy->max once and, if the lockless snapshot is inconsistent,
reduce the minimum to the observed maximum, along the lines of
cpufreq_driver_resolve_freq() (Christian Loehle)
- Fix a possible memory leak in the powernowk8_cpu_init() error paths
(Abdun Nihaal)
- Loosen the requirement on lowest nonlinear frequency != min freq in
the amd-pstate driver that is too tight for new systems some of
which actually have the lowest nonlinear frequency identical to the
minimum frequency (Mario Limonciello)
- Prevent amd-pstate from loading on unsupported hardware (Rong
Zhang)
- Address an initialization race in the schedutil governor when it
runs on multi-CPU cpufreq policies, by making it initialize all
per-CPU structures first and only then publish the per-CPU
utilization update hooks (Zhongqiu Han)"
* tag 'pm-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: powernow-k8: Fix possible memory leak in powernowk8_cpu_init()
ACPI: CPPC: Skip writes to unsupported performance controls
cpufreq/amd-pstate: Prevent the driver from loading on unsupported hardware
cpufreq/amd-pstate: Loosen requirement on lowest nonlinear frequency != min freq
cpufreq: schedutil: Publish util hooks only after all sg_cpu are initialized
cpufreq: cppc: Sanitize lockless policy limit snapshots
ACPI: CPPC: Check all controls for fast switching
Commit 14a8570564 ("sched/deadline: Use revised wakeup rule for
dl_server") applies the revised wakeup rule to any server, as a result
servers that are not running (dl_defer_running == 0) and start with a
deadline overflow get enqueued and can boost tasks as if they were
running, invalidating the defer rule and the documented state model.
Apply the revised wakeup rule only for deferrable servers that are
marked as running.
Fixes: 14a8570564 ("sched/deadline: Use revised wakeup rule for dl_server")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: Andrea Righi <arighi@nvidia.com>
Link: https://patch.msgid.link/20260522125833.264145-1-gmonaco@redhat.com
`audit_del_rule()` destroys `e->rule.exe` via `audit_remove_mark_rule()`
before unlinking the rule from RCU-visible filter lists and waiting for a
grace period. Concurrent readers in `audit_filter()` and
`audit_filter_rules()` still dereference `e->rule.exe`, while the fsnotify
mark can be freed on an independent lifetime path. This creates a
use-after-free window during rule deletion.
Fix this by unlinking the rule from the RCU-visible lists and invoking
`synchronize_rcu()` before calling `audit_remove_mark_rule()` (and other
rule removal helpers). This ensures that all existing RCU readers have
exited the critical section before any underlying resources are destroyed.
Cc: stable@vger.kernel.org
Fixes: 34d99af52a ("audit: implement audit by executable")
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
