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Frederic Weisbecker 9ad46f1fef perf: Fix event leak upon exec and file release
commit 3a5465418f upstream.

The perf pending task work is never waited upon the matching event
release. In the case of a child event, released via free_event()
directly, this can potentially result in a leaked event, such as in the
following scenario that doesn't even require a weak IRQ work
implementation to trigger:

schedule()
   prepare_task_switch()
=======> <NMI>
      perf_event_overflow()
         event->pending_sigtrap = ...
         irq_work_queue(&event->pending_irq)
<======= </NMI>
      perf_event_task_sched_out()
          event_sched_out()
              event->pending_sigtrap = 0;
              atomic_long_inc_not_zero(&event->refcount)
              task_work_add(&event->pending_task)
   finish_lock_switch()
=======> <IRQ>
   perf_pending_irq()
      //do nothing, rely on pending task work
<======= </IRQ>

begin_new_exec()
   perf_event_exit_task()
      perf_event_exit_event()
         // If is child event
         free_event()
            WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1)
            // event is leaked

Similar scenarios can also happen with perf_event_remove_on_exec() or
simply against concurrent perf_event_release().

Fix this with synchonizing against the possibly remaining pending task
work while freeing the event, just like is done with remaining pending
IRQ work. This means that the pending task callback neither need nor
should hold a reference to the event, preventing it from ever beeing
freed.

Fixes: 517e6a301f ("perf: Fix perf_pending_task() UaF")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240621091601.18227-5-frederic@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-19 05:45:19 +02:00
arch KVM: VMX: Split out the non-virtualization part of vmx_interrupt_blocked() 2024-08-19 05:45:14 +02:00
block block: initialize integrity buffer to zero before writing it to media 2024-08-19 05:44:50 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: aead,cipher - zeroize key buffer after use 2024-07-18 13:07:27 +02:00
Documentation dt-bindings: thermal: correct thermal zone node name limit 2024-08-19 05:45:10 +02:00
drivers scsi: qla2xxx: validate nvme_local_port correctly 2024-08-19 05:45:18 +02:00
fs fs/ntfs3: Update log->page_{mask,bits} if log->page_size changed 2024-08-19 05:45:16 +02:00
include perf: Fix event leak upon exec and file release 2024-08-19 05:45:19 +02:00
init init/main.c: Fix potential static_command_line memory overflow 2024-04-27 17:05:28 +02:00
io_uring io_uring: tighten task exit cancellations 2024-08-19 05:45:14 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel perf: Fix event leak upon exec and file release 2024-08-19 05:45:19 +02:00
lib kobject_uevent: Fix OOB access within zap_modalias_env() 2024-08-19 05:45:17 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/numa_balancing: teach mpol_to_str about the balancing mode 2024-08-19 05:45:17 +02:00
net ipv6: take care of scope when choosing the src addr 2024-08-19 05:45:11 +02:00
samples Add gitignore file for samples/fanotify/ subdirectory 2024-07-27 10:46:16 +02:00
scripts kbuild: Fix '-S -c' in x86 stack protector scripts 2024-08-19 05:45:16 +02:00
security task_work: s/task_work_cancel()/task_work_cancel_func()/ 2024-08-19 05:45:13 +02:00
sound ALSA: usb-audio: Add a quirk for Sonix HD USB Camera 2024-08-19 05:45:15 +02:00
tools tools/memory-model: Fix bug in lock.cat 2024-08-19 05:45:15 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-10 16:18:34 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS trace: Relocate event helper files 2024-04-10 16:19:24 +02:00
Makefile Linux 5.15.164 2024-07-27 10:46:18 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.