Elena Reshetova
ca3bb3d027
perf/ring_buffer: Convert ring_buffer.aux_refcount to refcount_t ...
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable ring_buffer.aux_refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
** Important note for maintainers:
Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts. Please check Documentation/core-api/refcount-vs-atomic.rst
for more information.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.
For the ring_buffer.aux_refcount it might make a difference
in following places:
- perf_aux_output_begin(): increment in refcount_inc_not_zero() only
guarantees control dependency on success vs. fully ordered
atomic counterpart
- rb_free_aux(): decrement in refcount_dec_and_test() only
provides RELEASE ordering and ACQUIRE ordering + control dependency
on success vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: namhyung@kernel.org
Link: https://lkml.kernel.org/r/1548678448-24458-4-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-04 08:46:17 +01:00
Merge branch 'perf/urgent' into perf/core, to pick up fixes
2019-02-04 08:45:42 +01:00
Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2018-12-29 10:57:20 -08:00
kvm_config: add CONFIG_VIRTIO_MENU
2018-10-24 20:55:56 -04:00
kdb: use bool for binary state indicators
2018-12-30 08:31:52 +00:00
swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit
2019-01-16 09:59:17 -05:00
perf/ring_buffer: Convert ring_buffer.aux_refcount to refcount_t
2019-02-04 08:46:17 +01:00
genirq/irqdesc: Fix double increment in alloc_descs()
2019-01-18 00:43:09 +01:00
livepatch: Replace synchronize_sched() with synchronize_rcu()
2018-12-01 12:38:50 -08:00
locking/rwsem: Fix (possible) missed wakeup
2019-01-21 11:15:39 +01:00
mm: convert totalram_pages and totalhigh_pages variables to atomic
2018-12-28 12:11:47 -08:00
Remove 'type' argument from access_ok() function
2019-01-03 18:57:57 -08:00
rcutorture: Don't do busted forward-progress testing
2018-12-01 12:45:42 -08:00
Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-02-03 09:02:03 -08:00
posix-cpu-timers: Unbreak timer rearming
2019-01-15 16:34:37 +01:00
perf: Make perf_event_output() propagate the output() return
2019-01-21 17:00:57 -03:00
audit: remove duplicated include from audit.c
2018-12-14 12:09:30 -05:00
audit: use current whenever possible
2018-11-26 18:41:21 -05:00
audit: minimize our use of audit_log_format()
2018-11-26 18:40:00 -05:00
audit: minimize our use of audit_log_format()
2018-11-26 18:40:00 -05:00
audit: minimize our use of audit_log_format()
2018-11-26 18:40:00 -05:00
audit: use current whenever possible
2018-11-26 18:41:21 -05:00
kbuild: fix kernel/bounds.c 'W=1' warning
2018-10-31 08:54:14 -07:00
make 'user_access_begin()' do 'access_ok()'
2019-01-04 12:56:09 -08:00
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
2019-01-30 19:27:00 +01:00
kernel/crash_core.c: print timestamp using time64_t
2018-08-22 10:52:47 -07:00
cred: export get_task_cred().
2018-12-19 13:52:44 -05:00
delayacct: track delays from thrashing cache pages
2018-10-26 16:26:32 -07:00
kernel/exit.c: release ptraced tasks before zap_pid_ns_processes
2019-02-01 15:46:23 -08:00
kernel/fail_function.c: remove meaningless null pointer check before debugfs_remove_recursive
2018-10-31 08:54:12 -07:00
Merge branch 'akpm' (patches from Andrew)
2019-01-08 18:58:29 -08:00
PM / reboot: Eliminate race between reboot and suspend
2018-08-06 12:35:20 +02:00
futex: Fix (possible) missed wakeup
2019-01-21 11:15:38 +01:00
kernel/hung_task.c: break RCU locks based on jiffies
2019-01-04 13:13:45 -08:00
jump_label: move 'asm goto' support test to Kconfig
2019-01-06 09:46:51 +09:00
bpf: Add module name [bpf] to ksymbols for bpf programs
2019-01-21 17:38:56 -03:00
kconfig: warn no new line at end of file
2018-12-15 17:44:35 +09:00
kernel/kcov.c: mark write_comp_data() as notrace
2019-01-04 13:13:47 -08:00
kexec: add call to LSM hook in original kexec_load syscall
2018-07-16 12:31:57 -07:00
mm: convert totalram_pages and totalhigh_pages variables to atomic
2018-12-28 12:11:47 -08:00
kexec_file: kexec_walk_memblock() only walks a dedicated region at kdump
2018-12-06 14:38:50 +00:00
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-12-26 14:45:18 -08:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-08-13 11:25:07 -07:00
kbuild: change filechk to surround the given command with { }
2019-01-06 09:46:51 +09:00
mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
2018-12-28 12:11:52 -08:00
modsign: log module name in the event of an error
2018-07-02 11:36:17 +02:00
jump_label: move 'asm goto' support test to Kconfig
2019-01-06 09:46:51 +09:00
modsign: use all trusted keys to verify module signature
2018-11-07 14:41:41 +01:00
padata: clean an indentation issue, remove extraneous space
2018-11-16 14:11:04 +08:00
kernel/sysctl: add panic_print into sysctl
2019-01-04 13:13:47 -08:00
Fix failure path in alloc_pid()
2018-12-28 12:42:30 -08:00
signal: Use group_send_sig_info to kill all processes in a pid namespace
2018-09-16 16:08:25 +02:00
mm: remove include/linux/bootmem.h
2018-10-31 08:54:16 -07:00
Remove 'type' argument from access_ok() function
2019-01-03 18:57:57 -08:00
kernel/reboot.c: export pm_power_off_prepare
2018-09-11 16:13:24 +01:00
kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable
2018-12-28 12:11:49 -08:00
Remove 'type' argument from access_ok() function
2019-01-03 18:57:57 -08:00
seccomp: fix UAF in user-trap code
2019-01-15 09:43:12 -08:00
Remove 'type' argument from access_ok() function
2019-01-03 18:57:57 -08:00
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
2019-01-30 19:27:00 +01:00
smpboot: Remove cpumask from the API
2018-07-03 09:20:44 +02:00
Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-10-25 11:43:47 -07:00
stackleak: Mark stackleak_track_stack() as notrace
2018-12-05 19:31:44 -08:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-08-13 11:25:07 -07:00
kernel/sys.c: Clarify that UNAME26 does not generate unique versions anymore
2019-01-14 10:38:03 +12:00
y2038: socket: Add compat_sys_recvmmsg_time64
2018-12-18 16:13:04 +01:00
kernel/sysctl: add panic_print into sysctl
2019-01-04 13:13:47 -08:00
kernel/sysctl: add panic_print into sysctl
2019-01-04 13:13:47 -08:00
torture: Remove unnecessary "ret" variables
2018-12-01 12:45:35 -08:00
tracing: Replace synchronize_sched() and call_rcu_sched()
2018-11-27 09:21:41 -08:00
umh: add exit routine for UMH process
2019-01-11 18:05:40 -08:00
smp,cpumask: introduce on_each_cpu_cond_mask
2018-10-09 16:51:11 +02:00
userns: use irqsave variant of refcount_dec_and_lock()
2018-08-22 10:52:47 -07:00
userns: also map extents in the reverse map to kernel IDs
2018-11-07 23:51:16 -06:00
sys: don't hold uts_sem while accessing userspace memory
2018-08-11 02:05:53 -05:00
watchdog: Mark watchdog touch functions as notrace
2018-08-30 12:56:40 +02:00
watchdog: Mark watchdog touch functions as notrace
2018-08-30 12:56:40 +02:00
psi: fix aggregation idle shut-off
2019-02-01 15:46:23 -08:00
psi: fix aggregation idle shut-off
2019-02-01 15:46:23 -08:00
ca3bb3d027