Christian Brauner
53df781e0b
pidfd: check pid has attached task in fdinfo
...
commit 3d6d8da48d0b214d65ea0227d47228abc75d7c88 upstream.
Currently, when a task is dead we still print the pid it used to use in
the fdinfo files of its pidfds. This doesn't make much sense since the
pid may have already been reused. So verify that the task is still alive
by introducing the pid_has_task() helper which will be used by other
callers in follow-up patches.
If the task is not alive anymore, we will print -1. This allows us to
differentiate between a task not being present in a given pid namespace
- in which case we already print 0 - and a task having been reaped.
Note that this uses PIDTYPE_PID for the check. Technically, we could've
checked PIDTYPE_TGID since pidfds currently only refer to thread-group
leaders but if they won't anymore in the future then this check becomes
problematic without it being immediately obvious to non-experts imho. If
a thread is created via clone(CLONE_THREAD) than struct pid has a single
non-empty list pid->tasks[PIDTYPE_PID] and this pid can't be used as a
PIDTYPE_TGID meaning pid->tasks[PIDTYPE_TGID] will return NULL even
though the thread-group leader might still be very much alive. So
checking PIDTYPE_PID is fine and is easier to maintain should we ever
allow pidfds to refer to threads.
Cc: Jann Horn <jannh@google.com>
Cc: Christian Kellner <christian@kellner.me>
Cc: linux-api@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20191017101832.5985-1-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04 14:32:36 +02:00
..
bpf
bpf: fix potential error return
2025-01-09 13:23:36 +01:00
cgroup
cgroup: Fix compilation issue due to cgroup_mutex not being exported
2025-06-04 14:32:29 +02:00
configs
debug
kdb: Use the passed prompt in kdb_position_cursor()
2024-08-19 05:33:40 +02:00
dma
dma: fix call order in dmam_free_coherent
2024-08-19 05:33:41 +02:00
events
perf/ring_buffer: Allow the EPOLLRDNORM flag for poll
2025-04-10 14:29:40 +02:00
gcov
gcov: add support for GCC 14
2024-07-05 09:08:24 +02:00
irq
genirq/irqdesc: Honor caller provided affinity in alloc_desc()
2024-08-19 05:33:52 +02:00
livepatch
livepatch: fix race between fork and KLP transition
2022-10-26 13:22:18 +02:00
locking
locking/lockdep: Decrease nr_unused_locks if lock unused in zap_class()
2025-05-02 07:39:15 +02:00
power
PM: hibernate: Add error handling for syscore_suspend()
2025-03-13 12:42:59 +01:00
printk
printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX
2025-03-13 12:43:02 +01:00
rcu
rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
2025-06-04 14:32:34 +02:00
sched
sched/deadline: Use online cpus for validating runtime
2025-04-10 14:29:42 +02:00
time
posix-timers: Add cond_resched() to posix_timer_add() search loop
2025-06-04 14:32:31 +02:00
trace
tracing: Fix oob write in trace_seq_to_buffer()
2025-06-04 14:32:24 +02:00
.gitignore
kbuild: update config_data.gz only when the content of .config is changed
2021-05-11 14:04:16 +02:00
acct.c
acct: perform last write from workqueue
2025-03-13 12:43:26 +01:00
async.c
treewide: Remove uninitialized_var() usage
2023-06-09 10:29:01 +02:00
audit.c
audit: Send netlink ACK before setting connection in auditd_set
2024-02-23 08:24:54 +01:00
audit.h
audit: log AUDIT_TIME_* records only from rules
2022-04-15 14:18:04 +02:00
audit_fsnotify.c
audit: fix potential double free on error path from fsnotify_add_inode_mark
2022-09-05 10:27:38 +02:00
audit_tree.c
audit: move put_tree() to avoid trim_trees refcount underflow and UAF
2021-09-03 10:08:16 +02:00
audit_watch.c
audit: don't WARN_ON_ONCE(!current->mm) in audit_exe_compare()
2023-11-28 16:50:18 +00:00
auditfilter.c
auditsc.c
audit: fix possible soft lockup in __audit_inode_child()
2023-09-23 10:59:46 +02:00
backtracetest.c
treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()
2023-04-20 12:07:32 +02:00
bounds.c
bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS
2024-05-02 16:18:37 +02:00
capability.c
compat.c
sched_getaffinity: don't assume 'cpumask_size()' is fully initialized
2023-04-05 11:16:42 +02:00
configs.c
context_tracking.c
cpu.c
hrtimers: Handle CPU state correctly on hotplug
2025-02-01 18:18:51 +01:00
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
cred: switch to using atomic_long_t
2023-12-20 15:41:18 +01:00
delayacct.c
dma.c
exec_domain.c
exit.c
mm: optimize the redundant loop of mm_update_owner_next()
2024-07-18 11:40:51 +02:00
extable.c
kernel/extable.c: use address-of operator on section symbols
2023-06-09 10:29:01 +02:00
fail_function.c
kernel/fail_function: fix memory leak with using debugfs_lookup()
2023-03-11 16:44:15 +01:00
fork.c
pidfd: check pid has attached task in fdinfo
2025-06-04 14:32:36 +02:00
freezer.c
futex.c
treewide: Remove uninitialized_var() usage
2023-06-09 10:29:01 +02:00
gen_kheaders.sh
kheaders: Ignore silly-rename files
2025-02-01 18:18:51 +01:00
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec.c
kexec_core.c
kexec: fix a memory leak in crash_shrink_memory()
2023-07-27 08:37:10 +02:00
kexec_elf.c
kexec: initialize ELF lowest address to ULONG_MAX
2025-04-10 14:29:41 +02:00
kexec_file.c
kexec: support purgatories with .text.hot sections
2023-06-21 15:44:10 +02:00
kexec_internal.h
kheaders.c
kheaders: Use array declaration instead of char
2023-05-17 11:35:33 +02:00
kmod.c
kprobes.c
kprobes: Fix possible use-after-free issue on kprobe registration
2024-05-02 16:18:30 +02:00
ksysfs.c
kthread.c
kthread: fix task state in kthread worker if being frozen
2024-11-08 16:20:30 +01:00
latencytop.c
Makefile
kbuild: update config_data.gz only when the content of .config is changed
2021-05-11 14:04:16 +02:00
module-internal.h
module.c
modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules
2023-09-23 10:59:36 +02:00
module_signature.c
module: harden ELF info handling
2021-04-07 14:47:38 +02:00
module_signing.c
module: harden ELF info handling
2021-04-07 14:47:38 +02:00
notifier.c
nsproxy.c
padata.c
padata: fix sysfs store callback check
2025-03-13 12:42:56 +01:00
panic.c
panic: Flush kernel log buffer at the end
2024-04-13 12:51:37 +02:00
params.c
module: ensure that kobject_put() is safe for module type kobjects
2025-06-04 14:32:27 +02:00
pid.c
pid_namespace.c
memcg: enable accounting for pids in nested pid namespaces
2021-09-22 12:26:37 +02:00
profile.c
profiling: fix shift too large makes kernel panic
2022-08-25 11:18:02 +02:00
ptrace.c
ptrace: Reimplement PTRACE_KILL by always sending SIGKILL
2022-06-14 18:11:24 +02:00
range.c
reboot.c
kernel/reboot: emergency_restart: Set correct system_state
2023-11-28 16:50:19 +00:00
relay.c
relayfs: fix out-of-bounds access in relay_file_read
2023-05-17 11:35:58 +02:00
resource.c
resource: fix region_intersects() vs add_memory_driver_managed()
2024-11-08 16:20:46 +01:00
rseq.c
seccomp.c
seccomp: Invalidate seccomp mode to catch death failures
2022-02-16 12:52:53 +01:00
signal.c
signal: Replace BUG_ON()s
2024-11-08 16:20:38 +01:00
smp.c
smp: Add missing destroy_work_on_stack() call in smp_call_on_cpu()
2024-09-12 11:03:54 +02:00
smpboot.c
kthread: Extract KTHREAD_IS_PER_CPU
2021-02-07 15:35:49 +01:00
smpboot.h
softirq.c
tasklet: Introduce new initialization API
2025-03-13 12:43:04 +01:00
stackleak.c
stacktrace.c
stop_machine.c
sys.c
getrusage: use sig->stats_lock rather than lock_task_sighand()
2024-03-15 10:48:19 -04:00
sys_ni.c
kernel/sys_ni: add compat entry for fadvise64_64
2022-09-05 10:27:38 +02:00
sysctl-test.c
sysctl.c
sched/rt: Disallow writing invalid values to sched_rt_period_us
2024-03-01 13:13:33 +01:00
sysctl_binary.c
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing
2021-07-14 16:53:08 +02:00
tsacct.c
taskstats: Cleanup the use of task->exit_code
2022-02-23 11:59:57 +01:00
ucount.c
uid16.c
uid16.h
umh.c
up.c
smp: Fix smp_call_function_single_async prototype
2021-05-14 09:44:33 +02:00
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c
watchdog: export lockup_detector_reconfigure
2022-08-25 11:18:37 +02:00
watchdog_hld.c
watchdog/perf: properly initialize the turbo mode timestamp and rearm counter
2024-08-19 05:33:39 +02:00
workqueue.c
workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()
2023-10-25 11:53:18 +02:00
workqueue_internal.h