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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, anil.s.keshavamurthy@intel.com,
	davem@davemloft.net, linux-mm@kvack.org, mhiramat@kernel.org,
	mm-commits@vger.kernel.org, naveen.n.rao@linux.ibm.com,
	rostedt@goodmis.org, songliubraving@fb.com,
	songmuchun@bytedance.com, stable@vger.kernel.org,
	torvalds@linux-foundation.org, zhouchengming@bytedance.com
Subject: [patch 08/15] kprobes: fix kill kprobe which has been marked as gone
Date: Fri, 18 Sep 2020 21:20:21 -0700
Message-ID: <20200919042021.X10NZatlE%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200918211925.7e97f0ef63d92f5cfe5ccbc5@linux-foundation.org>

From: Muchun Song <songmuchun@bytedance.com>
Subject: kprobes: fix kill kprobe which has been marked as gone

If a kprobe is marked as gone, we should not kill it again.  Otherwise, we
can disarm the kprobe more than once.  In that case, the statistics of
kprobe_ftrace_enabled can unbalance which can lead to that kprobe do not
work.

Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com
Fixes: e8386a0cb22f ("kprobes: support probing module __exit function")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Song Liu <songliubraving@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/kprobes.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/kernel/kprobes.c~kprobes-fix-kill-kprobe-which-has-been-marked-as-gone
+++ a/kernel/kprobes.c
@@ -2140,6 +2140,9 @@ static void kill_kprobe(struct kprobe *p
 
 	lockdep_assert_held(&kprobe_mutex);
 
+	if (WARN_ON_ONCE(kprobe_gone(p)))
+		return;
+
 	p->flags |= KPROBE_FLAG_GONE;
 	if (kprobe_aggrprobe(p)) {
 		/*
@@ -2419,7 +2422,10 @@ static int kprobes_module_callback(struc
 	mutex_lock(&kprobe_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
-		hlist_for_each_entry(p, head, hlist)
+		hlist_for_each_entry(p, head, hlist) {
+			if (kprobe_gone(p))
+				continue;
+
 			if (within_module_init((unsigned long)p->addr, mod) ||
 			    (checkcore &&
 			     within_module_core((unsigned long)p->addr, mod))) {
@@ -2436,6 +2442,7 @@ static int kprobes_module_callback(struc
 				 */
 				kill_kprobe(p);
 			}
+		}
 	}
 	if (val == MODULE_STATE_GOING)
 		remove_module_kprobe_blacklist(mod);
_

  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-19  4:19 incoming Andrew Morton
2020-09-19  4:20 ` [patch 01/15] mailmap: add older email addresses for Kees Cook Andrew Morton
2020-09-19  4:20 ` [patch 02/15] ksm: reinstate memcg charge on copied pages Andrew Morton
2020-09-19  4:20 ` [patch 03/15] mm: migration of hugetlbfs page skip memcg Andrew Morton
2020-09-19  4:20 ` [patch 04/15] shmem: shmem_writepage() split unlikely i915 THP Andrew Morton
2020-09-19  4:20 ` [patch 05/15] mm: fix check_move_unevictable_pages() on THP Andrew Morton
2020-09-19  4:20 ` [patch 06/15] mlock: fix unevictable_pgs event counts " Andrew Morton
2020-09-19  4:20 ` [patch 07/15] tmpfs: restore functionality of nr_inodes=0 Andrew Morton
2020-09-19  4:20 ` Andrew Morton [this message]
2020-09-19  4:20 ` [patch 09/15] mm/thp: fix __split_huge_pmd_locked() for migration PMD Andrew Morton
2020-09-19  4:20 ` [patch 10/15] selftests/vm: fix display of page size in map_hugetlb Andrew Morton
2020-09-19  4:20 ` [patch 11/15] mm/memory_hotplug: drain per-cpu pages again during memory offline Andrew Morton
2020-09-19  4:20 ` [patch 12/15] ftrace: let ftrace_enable_sysctl take a kernel pointer buffer Andrew Morton
2020-09-19  4:20 ` [patch 13/15] stackleak: let stack_erasing_sysctl " Andrew Morton
2020-09-19  4:20 ` [patch 14/15] fs/fs-writeback.c: adjust dirtytime_interval_handler definition to match prototype Andrew Morton
2020-09-19  4:20 ` [patch 15/15] kcsan: kconfig: move to menu 'Generic Kernel Debugging Instruments' Andrew Morton

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