Date: Sun, 10 Aug 2025 23:23:41 GMT
From: Alan Cox <alc@FreeBSD.org>
To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org
Subject: git: f406b54c806a - stable/14 - pmap_enter_{l2,pde}: correct the handling of an error case
Message-ID: <202508102323.57ANNfvk054097@gitrepo.freebsd.org>
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The branch stable/14 has been updated by alc: URL: https://cgit.FreeBSD.org/src/commit/?id=f406b54c806a3348ef4d4aab5e7290ce74ba9d71 commit f406b54c806a3348ef4d4aab5e7290ce74ba9d71 Author: Alan Cox <alc@FreeBSD.org> AuthorDate: 2025-07-16 08:08:49 +0000 Commit: Alan Cox <alc@FreeBSD.org> CommitDate: 2025-08-10 16:01:06 +0000 pmap_enter_{l2,pde}: correct the handling of an error case When pmap_enter_object()'s call to pmap_enter_{l2,pde}() fails to create a managed mapping within the kernel address space due to the inability to allocate a PV entry, it needs to remove the kernel page table page from the pmap's trie of idle page table pages. Previously, it did not. (cherry picked from commit 5a846c48f209d04dad36aa35a9968f557c4516f7) --- sys/amd64/amd64/pmap.c | 11 +++++++++++ sys/arm64/arm64/pmap.c | 12 ++++++++++++ 2 files changed, 23 insertions(+) diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index ba0ce76c5335..8aea7ad6d622 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -7500,6 +7500,9 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde, u_int flags, PG_RW = pmap_rw_bit(pmap); KASSERT((newpde & (pmap_modified_bit(pmap) | PG_RW)) != PG_RW, ("pmap_enter_pde: newpde is missing PG_M")); + KASSERT((flags & (PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM)) != + PMAP_ENTER_NORECLAIM, + ("pmap_enter_pde: flags is missing PMAP_ENTER_NOREPLACE")); PG_V = pmap_valid_bit(pmap); PMAP_LOCK_ASSERT(pmap, MA_OWNED); @@ -7629,6 +7632,14 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde, u_int flags, if (!pmap_pv_insert_pde(pmap, va, newpde, flags, lockp)) { if (pdpg != NULL) pmap_abort_ptp(pmap, va, pdpg); + else { + KASSERT(va >= VM_MAXUSER_ADDRESS && + (*pde & (PG_PS | PG_V)) == PG_V, + ("pmap_enter_pde: invalid kernel PDE")); + mt = pmap_remove_pt_page(pmap, va); + KASSERT(mt != NULL, + ("pmap_enter_pde: missing kernel PTP")); + } if (uwptpg != NULL) { mt = pmap_remove_pt_page(pmap, va); KASSERT(mt == uwptpg, diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c index f8dec0d3a82b..05cb0df4a1ae 100644 --- a/sys/arm64/arm64/pmap.c +++ b/sys/arm64/arm64/pmap.c @@ -4822,6 +4822,9 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags, PMAP_LOCK_ASSERT(pmap, MA_OWNED); KASSERT(ADDR_IS_CANONICAL(va), ("%s: Address not in canonical form: %lx", __func__, va)); + KASSERT((flags & (PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM)) != + PMAP_ENTER_NORECLAIM, + ("pmap_enter_l2: flags is missing PMAP_ENTER_NOREPLACE")); if ((l2 = pmap_alloc_l2(pmap, va, &l2pg, (flags & PMAP_ENTER_NOSLEEP) != 0 ? NULL : lockp)) == NULL) { @@ -4928,6 +4931,15 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags, if (!pmap_pv_insert_l2(pmap, va, new_l2, flags, lockp)) { if (l2pg != NULL) pmap_abort_ptp(pmap, va, l2pg); + else { + KASSERT(ADDR_IS_KERNEL(va) && + (pmap_load(l2) & ATTR_DESCR_MASK) == + L2_TABLE, + ("pmap_enter_l2: invalid kernel L2E")); + mt = pmap_remove_pt_page(pmap, va); + KASSERT(mt != NULL, + ("pmap_enter_l2: missing kernel PTP")); + } if (uwptpg != NULL) { mt = pmap_remove_pt_page(pmap, va); KASSERT(mt == uwptpg,
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