git: b53b21e8f81a - main - amd64 pmap: Release PTP reference on leaf ptpage allocation failure

The branch main has been updated by bnovkov:

URL: https://cgit.FreeBSD.org/src/commit/?id=b53b21e8f81a8d2d233b99cee6426c2f64765a3c

commit b53b21e8f81a8d2d233b99cee6426c2f64765a3c
Author:     Bojan Novković <bnovkov@FreeBSD.org>
AuthorDate: 2024-06-13 15:58:49 +0000
Commit:     Bojan Novković <bnovkov@FreeBSD.org>
CommitDate: 2024-06-16 16:19:26 +0000

    amd64 pmap: Release PTP reference on leaf ptpage allocation failure
    
    aa3bcaa fixed an edge case invloving mlock() and superpage creation
    by creating and inserting a leaf pagetable page for mlock'd superpages.
    However, the code does not properly release the reference to the
    pagetable page in the error handling path.
    This commit fixes the issue by adding calls to 'pmap_abort_ptp'
    in the error handling path.
    
    Reported by: alc
    Approved by: markj (mentor)
    Fixes: aa3bcaa
    Differential Revision: https://reviews.freebsd.org/D45577
---
 sys/amd64/amd64/pmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 4d4ecc8ea4e2..dee208fc9145 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -7595,10 +7595,13 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde, u_int flags,
 	if ((newpde & PG_W) != 0 && pmap != kernel_pmap) {
 		uwptpg = pmap_alloc_pt_page(pmap, pmap_pde_pindex(va),
 		    VM_ALLOC_WIRED);
-		if (uwptpg == NULL)
+		if (uwptpg == NULL) {
+			pmap_abort_ptp(pmap, va, pdpg);
 			return (KERN_RESOURCE_SHORTAGE);
+		}
 		if (pmap_insert_pt_page(pmap, uwptpg, true, false)) {
 			pmap_free_pt_page(pmap, uwptpg, false);
+			pmap_abort_ptp(pmap, va, pdpg);
 			return (KERN_RESOURCE_SHORTAGE);
 		}