The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=a725d61825f32ea00d07a2064431a02fd640313a
commit a725d61825f32ea00d07a2064431a02fd640313a
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2024-08-16 05:45:52 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2024-08-21 15:19:36 +0000
rangelock: if CAS for removal failed, restart list iteration
Our next pointer is invalid and cannot be followed.
Tested by: markj, pho
Sponsored by: The FreeBSD Foundation
---
sys/kern/kern_rangelock.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/sys/kern/kern_rangelock.c b/sys/kern/kern_rangelock.c
index 2667bf30fb6f..d9042f364737 100644
--- a/sys/kern/kern_rangelock.c
+++ b/sys/kern/kern_rangelock.c
@@ -539,6 +539,7 @@ rl_r_validate(struct rangelock *lock, struct rl_q_entry *e,
bool trylock,
{
struct rl_q_entry *cur, *next, **prev;
+again:
prev = &e->rl_q_next;
cur = rl_q_load(prev);
MPASS(!rl_e_is_marked(cur)); /* nobody can unlock e yet */
@@ -551,9 +552,10 @@ rl_r_validate(struct rangelock *lock, struct rl_q_entry
*e, bool trylock,
if (rl_q_cas(prev, cur, next)) {
cur->rl_q_free = *free;
*free = cur;
+ cur = next;
+ continue;
}
- cur = next;
- continue;
+ goto again;
}
if (rl_e_is_rlock(cur)) {
prev = &cur->rl_q_next;
@@ -583,6 +585,7 @@ rl_w_validate(struct rangelock *lock, struct rl_q_entry *e,
{
struct rl_q_entry *cur, *next, **prev;
+again:
prev = (struct rl_q_entry **)&lock->head;
cur = rl_q_load(prev);
MPASS(!rl_e_is_marked(cur)); /* head is not marked */
@@ -595,9 +598,10 @@ rl_w_validate(struct rangelock *lock, struct rl_q_entry *e,
if (rl_q_cas(prev, cur, next)) {
cur->rl_q_next = *free;
*free = cur;
+ cur = next;
+ continue;
}
- cur = next;
- continue;
+ goto again;
}
if (cur->rl_q_end <= e->rl_q_start) {
prev = &cur->rl_q_next;
@@ -642,9 +646,10 @@ again:
#endif
cur->rl_q_free = *free;
*free = cur;
+ cur = next;
+ continue;
}
- cur = next;
- continue;
+ goto again;
}
}
