Eric Biggers
0e92a7e47a
wait: add wake_up_pollfree() ...
commit 42288cb44c4b5fff7653bc392b583a2b8bd6a8c0 upstream.
Several ->poll() implementations are special in that they use a
waitqueue whose lifetime is the current task, rather than the struct
file as is normally the case. This is okay for blocking polls, since a
blocking poll occurs within one task; however, non-blocking polls
require another solution. This solution is for the queue to be cleared
before it is freed, using 'wake_up_poll(wq, EPOLLHUP | POLLFREE);'.
However, that has a bug: wake_up_poll() calls __wake_up() with
nr_exclusive=1. Therefore, if there are multiple "exclusive" waiters,
and the wakeup function for the first one returns a positive value, only
that one will be called. That's *not* what's needed for POLLFREE;
POLLFREE is special in that it really needs to wake up everyone.
Considering the three non-blocking poll systems:
- io_uring poll doesn't handle POLLFREE at all, so it is broken anyway.
- aio poll is unaffected, since it doesn't support exclusive waits.
However, that's fragile, as someone could add this feature later.
- epoll doesn't appear to be broken by this, since its wakeup function
returns 0 when it sees POLLFREE. But this is fragile.
Although there is a workaround (see epoll), it's better to define a
function which always sends POLLFREE to all waiters. Add such a
function. Also make it verify that the queue really becomes empty after
all waiters have been woken up.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211209010455.42744-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-14 10:04:48 +01:00
bpf: Prevent increasing bpf_jit_limit above max
2021-11-26 11:48:20 +01:00
config: android: enable CONFIG_SECCOMP
2016-10-11 15:06:32 -07:00
kdb: Make memory allocations more robust
2021-03-03 17:44:31 +01:00
events: Reuse value read using READ_ONCE instead of re-reading it
2021-09-22 11:43:09 +02:00
gcov: add support for GCC 10.1
2020-09-23 08:46:14 +02:00
genirq: Disable interrupts for force threaded handlers
2021-03-24 10:59:26 +01:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
locking/lockdep: Avoid RCU-induced noinstr fail
2021-11-26 11:48:27 +01:00
PM: hibernate: use correct mode for swsusp_close()
2021-12-08 08:45:03 +01:00
printk/console: Allow to disable console output by using console="" or console=null
2021-11-12 13:18:02 +01:00
rcuperf: Fix cleanup path for invalid perf_type strings
2019-05-31 06:48:30 -07:00
wait: add wake_up_pollfree()
2021-12-14 10:04:48 +01:00
kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()
2021-03-24 10:59:25 +01:00
tracing: Check pid filtering when creating events
2021-12-08 08:45:03 +01:00
kernel/acct.c: fix the acct->needcheck check in check_free_space()
2018-01-10 09:29:51 +01:00
kernel/async.c: revert "async: simplify lowest_in_progress()"
2018-02-17 13:21:18 +01:00
audit: fix a net reference leak in audit_list_rules_send()
2021-04-07 12:05:41 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2021-04-07 12:05:41 +02:00
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
2020-10-01 20:40:07 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2021-04-07 12:05:41 +02:00
audit: print empty EXECVE args
2019-11-28 18:28:55 +01:00
kbuild: fix kernel/bounds.c 'W=1' warning
2018-11-13 11:16:57 -08:00
ptrace: Capture the ptracer's creds not PT_PTRACE_CAP
2017-01-06 10:40:13 +01:00
cgroup: Make rebind_subsystems() disable v2 controllers all at once
2021-11-26 11:48:32 +01:00
cgroup: pids: use atomic64_t for pids->limit
2019-12-21 10:42:02 +01:00
kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling
2020-12-29 13:44:50 +01:00
kernel/cpu_pm: Fix uninitted local in cpu_pm
2020-06-20 10:24:21 +02:00
sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs
2017-10-12 11:51:25 +02:00
memcg: account security cred as well to kmemcg
2020-01-12 11:24:13 +01:00
futex: Mark the begin of futex exit explicitly
2021-02-03 23:19:49 +01:00
kernel/extable.c: mark core_kernel_text notrace
2017-07-21 07:42:21 +02:00
mm/hugetlb: initialize hugetlb_usage in mm_init
2021-09-22 11:43:08 +02:00
freezer, oom: check TIF_MEMDIE on the correct task
2016-07-28 16:07:41 -07:00
mm, futex: fix shared futex pgoff on shmem huge page
2021-07-11 12:46:40 +02:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
kernel: hung_task.c: disable on suspend
2019-04-20 09:07:52 +02:00
jump_label: Invoke jump_label_test() via early_initcall()
2017-12-14 09:28:24 +01:00
kcov: ensure irq code sees a valid area
2018-08-03 07:55:12 +02:00
kexec: allow architectures to override boot mapping
2016-08-02 19:35:27 -04:00
objtool, x86: Add several functions and files to the objtool whitelist
2018-06-05 10:28:57 +02:00
kernel: kexec_file: fix error return code of kexec_calculate_store_digests()
2021-05-22 10:40:31 +02:00
usermodehelper: reset umask to default before executing user process
2020-10-14 09:48:14 +02:00
kprobes: Limit max data_size of the kretprobe instances
2021-12-08 08:45:06 +01:00
kexec: add a kexec_crash_loaded() function
2016-08-02 19:35:30 -04:00
kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()
2021-07-11 12:46:41 +02:00
elfcore: fix building with clang
2021-02-10 09:09:25 +01:00
Fix: Disable sys_membarrier when nohz_full is enabled
2017-03-12 06:41:45 +01:00
mm, devm_memremap_pages: kill mapping "System RAM" support
2019-01-13 10:03:51 +01:00
module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols
2021-03-03 17:44:44 +01:00
x86/mm: split vmalloc_sync_all()
2020-04-02 17:20:26 +02:00
padata: purge get_cpu and reorder_via_wq from padata_do_serial
2020-05-27 16:41:53 +02:00
panic: ensure preemption is disabled during panic()
2019-10-17 13:42:25 -07:00
pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()
2018-04-13 19:47:53 +02:00
memcg: enable accounting for pids in nested pid namespaces
2021-09-22 11:43:08 +02:00
profiling: fix shift-out-of-bounds bugs
2021-09-26 13:36:18 +02:00
ptrace: make ptrace() fail if the tracee changed its pid unexpectedly
2021-05-26 11:29:06 +02:00
reboot: fix overflow parsing reboot cpu number
2020-11-18 18:26:32 +01:00
kernel/relay.c: fix memleak on destroy relay channel
2020-08-26 10:29:03 +02:00
resource: fix integer overflow at reallocation
2018-04-24 09:34:09 +02:00
seccomp: Add missing return in non-void function
2021-03-03 17:44:43 +01:00
signal: Remove the bogus sigkill_pending in ptrace_stop
2021-11-26 11:48:24 +01:00
cpu/hotplug: Fix SMT supported evaluation
2018-08-15 18:14:53 +02:00
kthread/smpboot: do not park in kthread_create_on_cpu()
2016-10-11 15:06:33 -07:00
Mark HI and TASKLET softirq synchronous
2018-08-15 18:14:42 +02:00
stacktrace, lockdep: Fix address, newline ugliness
2017-02-14 15:25:42 -08:00
stop_machine: Use raw spinlocks
2018-08-03 07:55:24 +02:00
prctl: allow to setup brk for et_dyn executables
2021-09-26 13:36:18 +02:00
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
2016-09-13 14:41:36 +02:00
sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds
2020-07-09 09:35:55 +02:00
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
2016-08-02 19:35:02 -04:00
taskstats: fix data-race
2020-01-12 11:24:12 +01:00
torture: Convert torture_shutdown() to hrtimer
2016-08-22 10:01:49 -07:00
tracepoint: Do not fail unregistering a probe due to memory failure
2021-03-03 17:44:38 +01:00
kernel/ucount.c: mark user_header with kmemleak_ignore()
2017-06-17 06:41:51 +02:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
smp: Add function to execute a function synchronously on a CPU
2016-09-05 13:52:39 +02:00
userns: move user access out of the mutex
2018-09-09 20:01:24 +02:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
sys: don't hold uts_sem while accessing userspace memory
2018-09-09 20:01:24 +02:00
kernel/watchdog: prevent false hardlockup on overloaded system
2017-06-17 06:41:57 +02:00
kernel/watchdog: prevent false hardlockup on overloaded system
2017-06-17 06:41:57 +02:00
workqueue: fix UAF in pwq_unbound_release_workfn()
2021-08-04 11:58:01 +02:00
workqueue: Fix NULL pointer dereference
2017-11-15 15:53:17 +01:00
0e92a7e47a