From: Ye Bin <[email protected]>
There's a issue as follows when rmmod modules after ftrace disabled:
BUG: unable to handle page fault for address: fffffbfff805000d
PGD 817fcc067 P4D 817fcc067 PUD 817fc8067 PMD 101555067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
CPU: 4 UID: 0 PID: 2012 Comm: rmmod Tainted: G W OE
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
RIP: 0010:kprobes_module_callback+0x89/0x790
RSP: 0018:ffff88812e157d30 EFLAGS: 00010a02
RAX: 1ffffffff805000d RBX: dffffc0000000000 RCX: ffffffff86a8de90
RDX: ffffed1025c2af9b RSI: 0000000000000008 RDI: ffffffffc0280068
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1025c2af9a
R10: ffff88812e157cd7 R11: 205d323130325420 R12: 0000000000000002
R13: ffffffffc0290488 R14: 0000000000000002 R15: ffffffffc0280040
FS: 00007fbc450dd740(0000) GS:ffff888420331000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff805000d CR3: 000000010f624000 CR4: 00000000000006f0
Call Trace:
<TASK>
notifier_call_chain+0xc6/0x280
blocking_notifier_call_chain+0x60/0x90
__do_sys_delete_module.constprop.0+0x32a/0x4e0
do_syscall_64+0x5d/0xfa0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The above issue occurs because the kprobe was not removed from the hash
list after ftrace_disable.
To prevent the system from restarting unexpectedly after ftrace_disable,
in such cases, unregister_kprobe() ensures that the probe is removed from
the hash list, preventing subsequent access to already freed memory.
Fixes: 6f0f1dd71953 ("kprobes: Cleanup disabling and unregistering path")
Signed-off-by: Ye Bin <[email protected]>
---
kernel/kprobes.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ab8f9fc1f0d1..d735a608b810 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1731,8 +1731,30 @@ static int __unregister_kprobe_top(struct kprobe *p)
/* Disable kprobe. This will disarm it if needed. */
ap = __disable_kprobe(p);
- if (IS_ERR(ap))
- return PTR_ERR(ap);
+ if (IS_ERR(ap)) {
+ int ret = PTR_ERR(ap);
+
+ /*
+ * If ftrace disabled we need to delete kprobe node from
+ * hlist or aggregation list. If nodes are not removed when
+ * modules are removed, the already released nodes will
+ * remain in the linked list. Subsequent access to the
+ * linked list may then trigger exceptions.
+ */
+ if (ret != -ENODEV)
+ return ret;
+
+ ap = __get_valid_kprobe(p);
+ if (!ap)
+ return ret;
+
+ if (ap == p)
+ hlist_del_rcu(&ap->hlist);
+ else
+ list_del_rcu(&p->list);
+
+ return ret;
+ }
WARN_ON(ap != p && !kprobe_aggrprobe(ap));
--
2.34.1
