Eric W. Biederman
39beaea03e
signal: Always notice exiting tasks ...
commit 35634ffa1751b6efd8cf75010b509dcb0263e29b upstream.
Recently syzkaller was able to create unkillablle processes by
creating a timer that is delivered as a thread local signal on SIGHUP,
and receiving SIGHUP SA_NODEFERER. Ultimately causing a loop
failing to deliver SIGHUP but always trying.
Upon examination it turns out part of the problem is actually most of
the solution. Since 2.5 signal delivery has found all fatal signals,
marked the signal group for death, and queued SIGKILL in every threads
thread queue relying on signal->group_exit_code to preserve the
information of which was the actual fatal signal.
The conversion of all fatal signals to SIGKILL results in the
synchronous signal heuristic in next_signal kicking in and preferring
SIGHUP to SIGKILL. Which is especially problematic as all
fatal signals have already been transformed into SIGKILL.
Instead of dequeueing signals and depending upon SIGKILL to
be the first signal dequeued, first test if the signal group
has already been marked for death. This guarantees that
nothing in the signal queue can prevent a process that needs
to exit from exiting.
Cc: stable@vger.kernel.org
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Ref: ebf5ebe31d2c ("[PATCH] signal-fixes-2.5.59-A4")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-15 08:07:37 +01:00
bpf: check pending signals while verifying programs
2018-12-21 14:11:38 +01:00
config: android: enable CONFIG_SECCOMP
2016-10-11 15:06:32 -07:00
kdb: use memmove instead of overlapping memcpy
2018-12-08 13:05:05 +01:00
perf/core: Don't WARN() for impossible ring-buffer sizes
2019-02-12 19:45:01 +01:00
gcov: support GCC 7.1
2017-09-02 07:07:53 +02:00
genirq: Fix race on spurious interrupt detection
2018-11-13 11:17:01 -08:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
locking/qspinlock, x86: Provide liveness guarantee
2018-12-21 14:11:34 +01:00
PM / sleep: wakeup: Fix build error caused by missing SRCU support
2018-09-09 20:01:23 +02:00
printk: Fix panic caused by passing log_buf_len to command line
2018-11-13 11:17:01 -08:00
rcu: Call touch_nmi_watchdog() while printing stall warnings
2018-05-30 07:50:50 +02:00
sched/core: Allow __sched_setscheduler() in interrupts when PI is not used
2018-12-01 09:44:25 +01:00
timekeeping: Use proper seqcount initializer
2019-02-12 19:44:54 +01:00
tracing: Fix memory leak of instance function hash filters
2018-12-21 14:11:31 +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: return on memory error to avoid null pointer dereference
2018-05-30 07:50:49 +02:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-07-29 17:54:17 -07:00
audit: cleanup prune_tree_thread
2016-04-04 09:46:47 -04:00
audit: fix use-after-free in audit_add_watch
2018-09-26 08:36:37 +02:00
audit: allow not equal op for audit by executable
2018-08-03 07:55:25 +02:00
audit: allow not equal op for audit by executable
2018-08-03 07:55:25 +02:00
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: Fix deadlock in cpu hotplug path
2018-10-13 09:18:56 +02:00
cgroup/pids: remove spurious suspicious RCU usage warning
2017-03-26 13:05:58 +02:00
Revert "x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation"
2018-11-23 12:57:41 +01:00
sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs
2017-10-12 11:51:25 +02:00
cred: Reject inodes with invalid ids in set_create_file_as()
2016-06-30 18:05:09 -05:00
kernel/exit.c: release ptraced tasks before zap_pid_ns_processes
2019-02-06 17:33:29 +01:00
kernel/extable.c: mark core_kernel_text notrace
2017-07-21 07:42:21 +02:00
fork: record start_time late
2019-01-13 10:03:51 +01:00
freezer, oom: check TIF_MEMDIE on the correct task
2016-07-28 16:07:41 -07:00
futex: futex_wake_op, do not fail on invalid op
2018-11-10 07:42:54 -08:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
kernel/hung_task.c: break RCU locks based on jiffies
2019-02-12 19:44:59 +01:00
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
kexec: fix double-free when failing to relocate the purgatory
2016-09-01 17:52:01 -07:00
kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()
2018-11-13 11:16:50 -08:00
kexec: add a kexec_crash_loaded() function
2016-08-02 19:35:30 -04:00
kthread, tracing: Don't expose half-written comm when creating kthreads
2018-08-03 07:55:12 +02:00
kernel/watchdog.c: move hardlockup detector to separate file
2017-06-17 06:41:57 +02:00
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: exclude SHN_UNDEF symbols from kallsyms api
2018-10-03 17:01:48 -07:00
KEYS: Move the point of trust determination to __key_link()
2016-04-11 22:43:43 +01:00
padata: free correct variable
2017-05-20 14:28:40 +02:00
panic: avoid deadlocks in re-entrant console drivers
2018-12-29 13:40:16 +01:00
pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()
2018-04-13 19:47:53 +02:00
pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes
2017-05-25 15:44:38 +02:00
profile: Convert to hotplug state machine
2016-07-15 10:41:42 +02:00
ptrace: Properly initialize ptracer_cred on fork
2017-06-14 15:05:54 +02:00
kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE
2018-05-30 07:50:29 +02:00
resource: fix integer overflow at reallocation
2018-04-24 09:34:09 +02:00
seccomp: Move speculation migitation control to arch code
2018-05-22 16:58:02 +02:00
signal: Always notice exiting tasks
2019-02-15 08:07:37 +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
sys: don't hold uts_sem while accessing userspace memory
2018-09-09 20:01:24 +02:00
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
2016-09-13 14:41:36 +02:00
proc/sysctl: fix return error for proc_doulongvec_minmax()
2019-02-12 19:44:59 +01:00
kernel/sysctl_binary.c: use generic UUID library
2016-05-20 17:58:30 -07:00
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
2016-08-02 19:35:02 -04:00
taskstats: fix the length of cgroupstats_cmd_get_policy
2016-11-03 16:55:58 -04:00
torture: Convert torture_shutdown() to hrtimer
2016-08-22 10:01:49 -07:00
tracepoint: Do not warn on ENOMEM
2018-05-09 09:50:20 +02:00
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: use put_device() instead of kfree()
2018-05-30 07:50:36 +02:00
workqueue: Fix NULL pointer dereference
2017-11-15 15:53:17 +01:00
39beaea03e