Star64_linux/kernel
Oleg Nesterov fab840fc2d ptrace: PTRACE_DETACH should do flush_ptrace_hw_breakpoint(child)
Change ptrace_detach() to call flush_ptrace_hw_breakpoint(child).  This
frees the slots for non-ptrace PERF_TYPE_BREAKPOINT users, and this
ensures that the tracee won't be killed by SIGTRAP triggered by the
active breakpoints.

Test-case:

	unsigned long encode_dr7(int drnum, int enable, unsigned int type, unsigned int len)
	{
		unsigned long dr7;

		dr7 = ((len | type) & 0xf)
			<< (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE);
		if (enable)
			dr7 |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE));

		return dr7;
	}

	int write_dr(int pid, int dr, unsigned long val)
	{
		return ptrace(PTRACE_POKEUSER, pid,
				offsetof (struct user, u_debugreg[dr]),
				val);
	}

	void func(void)
	{
	}

	int main(void)
	{
		int pid, stat;
		unsigned long dr7;

		pid = fork();
		if (!pid) {
			assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0);
			kill(getpid(), SIGHUP);

			func();
			return 0x13;
		}

		assert(pid == waitpid(-1, &stat, 0));
		assert(WSTOPSIG(stat) == SIGHUP);

		assert(write_dr(pid, 0, (long)func) == 0);
		dr7 = encode_dr7(0, 1, DR_RW_EXECUTE, DR_LEN_1);
		assert(write_dr(pid, 7, dr7) == 0);

		assert(ptrace(PTRACE_DETACH, pid, 0,0) == 0);
		assert(pid == waitpid(-1, &stat, 0));
		assert(stat == 0x1300);

		return 0;
	}

Before this patch the child is killed after PTRACE_DETACH.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:26 -07:00
..
cpu idle: Enable interrupts in the weak arch_cpu_idle() implementation 2013-06-14 23:01:05 +02:00
debug
events perf: Drop sample rate when sampling is too slow 2013-06-23 11:52:57 +02:00
gcov
irq irqdomain refactoring for v3.11 2013-07-06 12:37:04 -07:00
power Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
sched Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-07-06 14:09:38 -07:00
time clocksource: Reselect clocksource when watchdog validated high-res capability 2013-07-05 11:09:28 +02:00
trace tracing: Fix outputting formats of x86-tsc and counter when use trace_clock 2013-06-11 13:58:46 -04:00
.gitignore
acct.c fs: Fix hang with BSD accounting on frozen filesystem 2013-05-04 14:57:58 -04:00
async.c
audit.c audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE 2013-06-12 16:29:45 -07:00
audit.h audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record 2013-07-09 10:33:19 -07:00
audit_tree.c kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules() 2013-06-12 16:29:46 -07:00
audit_watch.c
auditfilter.c audit: Fix decimal constant description 2013-07-09 10:33:19 -07:00
auditsc.c audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record 2013-07-09 10:33:19 -07:00
backtracetest.c
bounds.c
capability.c
cgroup.c cgroup: CGRP_ROOT_SUBSYS_BOUND should also be ignored when mounting an existing hierarchy 2013-06-29 14:06:10 -07:00
cgroup_freezer.c
compat.c
configs.c
context_tracking.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-06-20 08:18:35 -10:00
cpu.c CPU hotplug: provide a generic helper to disable/enable CPU hotplug 2013-06-12 16:29:44 -07:00
cpu_pm.c
cpuset.c Merge branch 'for-3.11-cpuset' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-07-02 20:04:25 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c ptrace: revert "Prepare to fix racy accesses on task breakpoints" 2013-07-09 10:33:26 -07:00
extable.c
fork.c kernel/fork.c:copy_process(): consolidate the lockless CLONE_THREAD checks 2013-07-03 16:08:03 -07:00
freezer.c freezer: skip waking up tasks with PF_FREEZER_SKIP set 2013-05-12 14:16:22 +02:00
futex.c futex: Use freezable blocking call 2013-06-25 23:11:19 +02:00
futex_compat.c
groups.c
hrtimer.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-07-06 14:09:38 -07:00
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH" 2013-05-28 08:50:00 +02:00
Kconfig.preempt
kexec.c
kmod.c usermodehelper: kill the sub_info->path[0] check 2013-07-03 16:08:02 -07:00
kprobes.c kprobes: handle empty/invalid input to debugfs "enabled" file 2013-07-03 16:07:46 -07:00
ksysfs.c
kthread.c
latencytop.c
lglock.c
lockdep.c lockdep: remove task argument from debug_check_no_locks_held 2013-05-12 14:16:21 +02:00
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
Makefile We get rid of the general module prefix confusion with a binary config option, 2013-05-05 10:58:06 -07:00
modsign_certificate.S
modsign_pubkey.c
module-internal.h
module.c kmemleak: No need for scanning specific module sections 2013-05-17 09:53:36 +01:00
module_signing.c
mutex-debug.c
mutex-debug.h
mutex.c mutex: Add w/w mutex slowpath debugging 2013-06-26 12:10:56 +02:00
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c panic: add cpu/pid to warn_slowpath_common in WARNING printk()s 2013-07-09 10:33:25 -07:00
params.c
pid.c kernel/pid.c: move statement 2013-07-03 16:08:05 -07:00
pid_namespace.c
posix-cpu-timers.c posix_timers: fix racy timer delta caching on task exit 2013-07-03 16:54:42 +02:00
posix-timers.c
printk.c kmsg: honor dmesg_restrict sysctl on /dev/kmsg 2013-06-12 16:29:44 -07:00
profile.c
ptrace.c ptrace: PTRACE_DETACH should do flush_ptrace_hw_breakpoint(child) 2013-07-09 10:33:26 -07:00
range.c range: Do not add new blank slot with add_range_with_merge 2013-06-18 11:32:10 -05:00
rcu.h
rcupdate.c Merge branches 'cbnum.2013.06.10a', 'doc.2013.06.10a', 'fixes.2013.06.10a', 'srcu.2013.06.10a' and 'tiny.2013.06.10a' into HEAD 2013-06-10 13:46:44 -07:00
rcutiny.c rcu: Shrink TINY_RCU by reworking CPU-stall ifdefs 2013-06-10 13:45:53 -07:00
rcutiny_plugin.h rcu: Shrink TINY_RCU by reworking CPU-stall ifdefs 2013-06-10 13:45:53 -07:00
rcutorture.c rcu: Remove srcu_read_lock_raw() and srcu_read_unlock_raw(). 2013-06-10 13:45:25 -07:00
rcutree.c drivers: avoid parsing names as kthread_run() format strings 2013-07-03 16:07:41 -07:00
rcutree.h rcu: Drive quiescent-state-forcing delay from HZ 2013-06-10 13:44:56 -07:00
rcutree_plugin.h Merge branches 'cbnum.2013.06.10a', 'doc.2013.06.10a', 'fixes.2013.06.10a', 'srcu.2013.06.10a' and 'tiny.2013.06.10a' into HEAD 2013-06-10 13:46:44 -07:00
rcutree_trace.c rcutrace: single_open() leaks 2013-05-05 00:16:35 -04:00
relay.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
res_counter.c
resource.c kernel/resource.c: remove the unneeded assignment in function __find_resource 2013-07-03 16:08:06 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c rtmutex: Document rt_mutex_adjust_prio_chain() 2013-05-28 09:23:52 +02:00
rtmutex.h
rtmutex_common.h
rwsem.c
seccomp.c
semaphore.c
signal.c sigtimedwait: use freezable blocking call 2013-05-12 14:16:23 +02:00
smp.c
smpboot.c
smpboot.h
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-07-02 16:14:35 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys.c exit.c: unexport __set_special_pids() 2013-07-03 16:08:02 -07:00
sys_ni.c unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE 2013-05-09 13:46:38 -04:00
sysctl.c perf: Drop sample rate when sampling is too slow 2013-06-23 11:52:57 +02:00
sysctl_binary.c switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE 2013-05-09 14:53:20 -04:00
task_work.c
taskstats.c
test_kprobes.c
time.c sched: Rename sched.c as sched/core.c in comments and Documentation 2013-06-19 12:58:42 +02:00
timeconst.bc
timer.c timer: Fix jiffies wrap behavior of round_jiffies_common() 2013-06-28 17:10:11 +02:00
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
wait.c Add wait_on_atomic_t() and wake_up_atomic_t() 2013-05-15 13:50:38 +01:00
watchdog.c
workqueue.c Merge branch 'for-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2013-07-02 19:53:30 -07:00
workqueue_internal.h sched: Rename sched.c as sched/core.c in comments and Documentation 2013-06-19 12:58:42 +02:00