The branch stable/13 has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=cec3990d347972c30558b135b1bc9954184fb5fe
commit cec3990d347972c30558b135b1bc9954184fb5fe
Author: Mark Johnston <mark...@gmail.com>
AuthorDate: 2021-03-11 15:34:28 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2021-03-14 01:09:29 +0000
vm_reserv: Fix list locking in vm_reserv_reclaim_contig()
The per-domain partpop queue is locked by the combination of the
per-domain lock and individual reservation mutexes.
vm_reserv_reclaim_contig() scans the queue looking for partially
populated reservations that can be reclaimed in order to satisfy the
caller's allocation.
During the scan, we drop the per-domain lock. At this point, the rvn
pointer may be invalidated. Take care to load rvn after re-acquiring
the per-domain lock.
While here, simplify the condition used to check whether a reservation
was dequeued while the per-domain lock was dropped.
Reviewed by: alc, kib
Reported by: gallatin
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29203
(cherry picked from commit 968079f253c11433d47bece4b41b46fcbf985903)
---
sys/vm/vm_reserv.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/sys/vm/vm_reserv.c b/sys/vm/vm_reserv.c
index e7f542a66fdb..a9602c3977df 100644
--- a/sys/vm/vm_reserv.c
+++ b/sys/vm/vm_reserv.c
@@ -1344,8 +1344,8 @@ vm_reserv_reclaim_contig(int domain, u_long npages,
vm_paddr_t low,
TAILQ_INSERT_AFTER(queue, rv, marker, partpopq);
vm_reserv_domain_unlock(domain);
vm_reserv_lock(rv);
- if (!rv->inpartpopq ||
- TAILQ_NEXT(rv, partpopq) != marker) {
+ if (TAILQ_PREV(marker, vm_reserv_queue, partpopq) !=
+ rv) {
vm_reserv_unlock(rv);
vm_reserv_domain_lock(domain);
rvn = TAILQ_NEXT(marker, partpopq);
@@ -1363,8 +1363,9 @@ vm_reserv_reclaim_contig(int domain, u_long npages,
vm_paddr_t low,
vm_reserv_unlock(rv);
return (true);
}
- vm_reserv_unlock(rv);
vm_reserv_domain_lock(domain);
+ rvn = TAILQ_NEXT(rv, partpopq);
+ vm_reserv_unlock(rv);
}
vm_reserv_domain_unlock(domain);
vm_reserv_domain_scan_unlock(domain);
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