The branch main has been updated by kib:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=ef9017aa174db96ee741b936b984f2b5d61dff9f

commit ef9017aa174db96ee741b936b984f2b5d61dff9f
Author:     Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2024-12-05 20:54:35 +0000
Commit:     Konstantin Belousov <k...@freebsd.org>
CommitDate: 2025-06-19 22:25:56 +0000

    pmap_growkernel(): do not panic immediately, optionally return the error
    
    Reviewed by:    markj
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D47935
---
 sys/amd64/amd64/pmap.c              | 40 +++++++++++++++++++++++++++++--------
 sys/arm/arm/pmap-v6.c               | 23 ++++++++++++++++++---
 sys/arm64/arm64/pmap.c              | 25 +++++++++++++++++++----
 sys/i386/i386/pmap.c                |  6 ++++--
 sys/i386/i386/pmap_base.c           | 14 +++++++++++--
 sys/i386/include/pmap_base.h        |  2 +-
 sys/powerpc/aim/mmu_radix.c         | 13 ++++++------
 sys/powerpc/include/mmuvar.h        |  4 ++--
 sys/powerpc/powerpc/pmap_dispatch.c | 19 +++++++++++++++++-
 sys/riscv/riscv/pmap.c              | 27 +++++++++++++++++++++----
 sys/vm/pmap.h                       |  2 +-
 sys/vm/vm_map.c                     |  9 +++++++--
 12 files changed, 148 insertions(+), 36 deletions(-)

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 2962f2823596..6d1c2d70d8c0 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -578,6 +578,11 @@ static pml4_entry_t *pti_pml4;
 static vm_pindex_t pti_pg_idx;
 static bool pti_finalized;
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 struct pmap_pkru_range {
        struct rs_el    pkru_rs_el;
        u_int           pkru_keyidx;
@@ -5124,17 +5129,19 @@ pmap_page_array_startup(long pages)
 /*
  * grow the number of kernel page table entries, if needed
  */
-void
-pmap_growkernel(vm_offset_t addr)
+static int
+pmap_growkernel_nopanic(vm_offset_t addr)
 {
        vm_paddr_t paddr;
        vm_page_t nkpg;
        pd_entry_t *pde, newpdir;
        pdp_entry_t *pdpe;
        vm_offset_t end;
+       int rv;
 
        TSENTER();
        mtx_assert(&kernel_map->system_mtx, MA_OWNED);
+       rv = KERN_SUCCESS;
 
        /*
         * The kernel map covers two distinct regions of KVA: that used
@@ -5162,7 +5169,7 @@ pmap_growkernel(vm_offset_t addr)
                end = KERNBASE + nkpt * NBPDR;
                if (end == 0) {
                        TSEXIT();
-                       return;
+                       return (rv);
                }
        } else {
                end = kernel_vm_end;
@@ -5177,7 +5184,7 @@ pmap_growkernel(vm_offset_t addr)
                 * nothing to do.
                 */
                TSEXIT();
-               return;
+               return (rv);
        }
 
        kasan_shadow_map(end, addr - end);
@@ -5188,8 +5195,10 @@ pmap_growkernel(vm_offset_t addr)
                        nkpg = pmap_alloc_pt_page(kernel_pmap,
                            pmap_pdpe_pindex(end), VM_ALLOC_INTERRUPT |
                                VM_ALLOC_NOFREE | VM_ALLOC_WIRED | 
VM_ALLOC_ZERO);
-                       if (nkpg == NULL)
-                               panic("pmap_growkernel: no memory to grow 
kernel");
+                       if (nkpg == NULL) {
+                               rv = KERN_RESOURCE_SHORTAGE;
+                               break;
+                       }
                        paddr = VM_PAGE_TO_PHYS(nkpg);
                        *pdpe = (pdp_entry_t)(paddr | X86_PG_V | X86_PG_RW |
                            X86_PG_A | X86_PG_M);
@@ -5208,8 +5217,11 @@ pmap_growkernel(vm_offset_t addr)
                nkpg = pmap_alloc_pt_page(kernel_pmap, pmap_pde_pindex(end),
                    VM_ALLOC_INTERRUPT | VM_ALLOC_NOFREE | VM_ALLOC_WIRED |
                        VM_ALLOC_ZERO);
-               if (nkpg == NULL)
-                       panic("pmap_growkernel: no memory to grow kernel");
+               if (nkpg == NULL) {
+                       rv = KERN_RESOURCE_SHORTAGE;
+                       break;
+               }
+
                paddr = VM_PAGE_TO_PHYS(nkpg);
                newpdir = paddr | X86_PG_V | X86_PG_RW | X86_PG_A | X86_PG_M;
                pde_store(pde, newpdir);
@@ -5226,6 +5238,18 @@ pmap_growkernel(vm_offset_t addr)
        else
                nkpt = howmany(end - KERNBASE, NBPDR);
        TSEXIT();
+       return (rv);
+}
+
+int
+pmap_growkernel(vm_offset_t addr)
+{
+       int rv;
+
+       rv = pmap_growkernel_nopanic(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
 }
 
 /***************************************************
diff --git a/sys/arm/arm/pmap-v6.c b/sys/arm/arm/pmap-v6.c
index a0158bb128e7..92eb0589f80b 100644
--- a/sys/arm/arm/pmap-v6.c
+++ b/sys/arm/arm/pmap-v6.c
@@ -1577,6 +1577,11 @@ static int sp_enabled = 1;
 SYSCTL_INT(_vm_pmap, OID_AUTO, sp_enabled, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
     &sp_enabled, 0, "Are large page mappings enabled?");
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 bool
 pmap_ps_enabled(pmap_t pmap __unused)
 {
@@ -2031,8 +2036,8 @@ pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, 
vm_prot_t prot)
 /*
  *  Grow the number of kernel L2 page table entries, if needed.
  */
-void
-pmap_growkernel(vm_offset_t addr)
+static int
+pmap_growkernel_nopanic(vm_offset_t addr)
 {
        vm_page_t m;
        vm_paddr_t pt2pg_pa, pt2_pa;
@@ -2085,7 +2090,7 @@ pmap_growkernel(vm_offset_t addr)
                        m = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                            VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                        if (m == NULL)
-                               panic("%s: no memory to grow kernel", __func__);
+                               return (KERN_RESOURCE_SHORTAGE);
                        m->pindex = pte1_index(kernel_vm_end) & ~PT2PG_MASK;
 
                        /*
@@ -2110,6 +2115,18 @@ pmap_growkernel(vm_offset_t addr)
                        break;
                }
        }
+       return (KERN_SUCCESS);
+}
+
+int
+pmap_growkernel(vm_offset_t addr)
+{
+       int rv;
+
+       rv = pmap_growkernel_nopanic(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
 }
 
 static int
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index a53e8b3684e3..d2e56a270f54 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -357,6 +357,11 @@ static u_int physmap_idx;
 static SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
     "VM/pmap parameters");
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 bool pmap_lpa_enabled __read_mostly = false;
 pt_entry_t pmap_sh_attr __read_mostly = ATTR_SH(ATTR_SH_IS);
 
@@ -3096,8 +3101,8 @@ SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG | 
CTLFLAG_RD | CTLFLAG_MPSAFE,
 /*
  * grow the number of kernel page table entries, if needed
  */
-void
-pmap_growkernel(vm_offset_t addr)
+static int
+pmap_growkernel_nopanic(vm_offset_t addr)
 {
        vm_page_t nkpg;
        pd_entry_t *l0, *l1, *l2;
@@ -3122,7 +3127,7 @@ pmap_growkernel(vm_offset_t addr)
                        nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                            VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                        if (nkpg == NULL)
-                               panic("pmap_growkernel: no memory to grow 
kernel");
+                               return (KERN_RESOURCE_SHORTAGE);
                        nkpg->pindex = pmap_l1_pindex(kernel_vm_end);
                        /* See the dmb() in _pmap_alloc_l3(). */
                        dmb(ishst);
@@ -3142,7 +3147,7 @@ pmap_growkernel(vm_offset_t addr)
                nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                    VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                if (nkpg == NULL)
-                       panic("pmap_growkernel: no memory to grow kernel");
+                       return (KERN_RESOURCE_SHORTAGE);
                nkpg->pindex = pmap_l2_pindex(kernel_vm_end);
                /* See the dmb() in _pmap_alloc_l3(). */
                dmb(ishst);
@@ -3154,6 +3159,18 @@ pmap_growkernel(vm_offset_t addr)
                        break;
                }
        }
+       return (KERN_SUCCESS);
+}
+
+int
+pmap_growkernel(vm_offset_t addr)
+{
+       int rv;
+
+       rv = pmap_growkernel_nopanic(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
 }
 
 /***************************************************
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 89701c1061b0..465b4d0f365b 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -2234,7 +2234,7 @@ __CONCAT(PMTYPE, release)(pmap_t pmap)
 /*
  * grow the number of kernel page table entries, if needed
  */
-static void
+static int
 __CONCAT(PMTYPE, growkernel)(vm_offset_t addr)
 {
        vm_paddr_t ptppaddr;
@@ -2258,7 +2258,7 @@ __CONCAT(PMTYPE, growkernel)(vm_offset_t addr)
                nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                    VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                if (nkpg == NULL)
-                       panic("pmap_growkernel: no memory to grow kernel");
+                       return (KERN_RESOURCE_SHORTAGE);
                nkpg->pindex = kernel_vm_end >> PDRSHIFT;
                nkpt++;
 
@@ -2273,6 +2273,8 @@ __CONCAT(PMTYPE, growkernel)(vm_offset_t addr)
                        break;
                }
        }
+
+       return (KERN_SUCCESS);
 }
 
 /***************************************************
diff --git a/sys/i386/i386/pmap_base.c b/sys/i386/i386/pmap_base.c
index f6252a7ca5da..cdbfd688f110 100644
--- a/sys/i386/i386/pmap_base.c
+++ b/sys/i386/i386/pmap_base.c
@@ -109,6 +109,7 @@ static SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD | 
CTLFLAG_MPSAFE, 0,
 #include <machine/vmparam.h>
 #include <vm/vm.h>
 #include <vm/vm_page.h>
+#include <vm/vm_param.h>
 #include <vm/pmap.h>
 #include <machine/pmap_base.h>
 
@@ -252,6 +253,11 @@ SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_spare, CTLFLAG_RD,
     "Current number of spare pv entries");
 #endif
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 struct pmap kernel_pmap_store;
 static struct pmap_methods *pmap_methods_ptr;
 
@@ -893,11 +899,15 @@ pmap_init_pat(void)
        pmap_methods_ptr->pm_init_pat();
 }
 
-void
+int
 pmap_growkernel(vm_offset_t addr)
 {
+       int rv;
 
-       pmap_methods_ptr->pm_growkernel(addr);
+       rv = pmap_methods_ptr->pm_growkernel(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
 }
 
 void
diff --git a/sys/i386/include/pmap_base.h b/sys/i386/include/pmap_base.h
index 1a13da16e39c..20f814195281 100644
--- a/sys/i386/include/pmap_base.h
+++ b/sys/i386/include/pmap_base.h
@@ -107,7 +107,7 @@ struct pmap_methods {
        void (*pm_remove_all)(vm_page_t);
        void (*pm_init)(void);
        void (*pm_init_pat)(void);
-       void (*pm_growkernel)(vm_offset_t);
+       int (*pm_growkernel)(vm_offset_t);
        void (*pm_invalidate_page)(pmap_t, vm_offset_t);
        void (*pm_invalidate_range)(pmap_t, vm_offset_t, vm_offset_t);
        void (*pm_invalidate_all)(pmap_t);
diff --git a/sys/powerpc/aim/mmu_radix.c b/sys/powerpc/aim/mmu_radix.c
index cda8dd1c0946..45f7bef8bcc9 100644
--- a/sys/powerpc/aim/mmu_radix.c
+++ b/sys/powerpc/aim/mmu_radix.c
@@ -480,7 +480,7 @@ static void mmu_radix_bootstrap(vm_offset_t, vm_offset_t);
 static void mmu_radix_copy_page(vm_page_t, vm_page_t);
 static void mmu_radix_copy_pages(vm_page_t *ma, vm_offset_t a_offset,
     vm_page_t *mb, vm_offset_t b_offset, int xfersize);
-static void mmu_radix_growkernel(vm_offset_t);
+static int mmu_radix_growkernel(vm_offset_t);
 static void mmu_radix_init(void);
 static int mmu_radix_mincore(pmap_t, vm_offset_t, vm_paddr_t *);
 static vm_offset_t mmu_radix_map(vm_offset_t *, vm_paddr_t, vm_paddr_t, int);
@@ -501,7 +501,7 @@ static struct pmap_funcs mmu_radix_methods = {
        .copy_page = mmu_radix_copy_page,
        .copy_pages = mmu_radix_copy_pages,
        .cpu_bootstrap = mmu_radix_cpu_bootstrap,
-       .growkernel = mmu_radix_growkernel,
+       .growkernel_nopanic = mmu_radix_growkernel,
        .init = mmu_radix_init,
        .map =                  mmu_radix_map,
        .mincore =              mmu_radix_mincore,
@@ -3560,7 +3560,7 @@ mmu_radix_extract_and_hold(pmap_t pmap, vm_offset_t va, 
vm_prot_t prot)
        return (m);
 }
 
-static void
+static int
 mmu_radix_growkernel(vm_offset_t addr)
 {
        vm_paddr_t paddr;
@@ -3571,7 +3571,7 @@ mmu_radix_growkernel(vm_offset_t addr)
        CTR2(KTR_PMAP, "%s(%#x)", __func__, addr);
        if (VM_MIN_KERNEL_ADDRESS < addr &&
                addr < (VM_MIN_KERNEL_ADDRESS + nkpt * L3_PAGE_SIZE))
-               return;
+               return (KERN_SUCCESS);
 
        addr = roundup2(addr, L3_PAGE_SIZE);
        if (addr - 1 >= vm_map_max(kernel_map))
@@ -3583,7 +3583,7 @@ mmu_radix_growkernel(vm_offset_t addr)
                        nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                            VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                        if (nkpg == NULL)
-                               panic("pmap_growkernel: no memory to grow 
kernel");
+                               return (KERN_RESOURCE_SHORTAGE);
                        nkpg->pindex = kernel_vm_end >> L2_PAGE_SIZE_SHIFT;
                        paddr = VM_PAGE_TO_PHYS(nkpg);
                        pde_store(l2e, paddr);
@@ -3602,7 +3602,7 @@ mmu_radix_growkernel(vm_offset_t addr)
                nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                    VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                if (nkpg == NULL)
-                       panic("pmap_growkernel: no memory to grow kernel");
+                       return (KERN_RESOURCE_SHORTAGE);
                nkpg->pindex = pmap_l3e_pindex(kernel_vm_end);
                paddr = VM_PAGE_TO_PHYS(nkpg);
                pde_store(l3e, paddr);
@@ -3614,6 +3614,7 @@ mmu_radix_growkernel(vm_offset_t addr)
                }
        }
        ptesync();
+       return (KERN_SUCCESS);
 }
 
 static MALLOC_DEFINE(M_RADIX_PGD, "radix_pgd", "radix page table root 
directory");
diff --git a/sys/powerpc/include/mmuvar.h b/sys/powerpc/include/mmuvar.h
index 4d0c3d90616f..9cf7a682ddd5 100644
--- a/sys/powerpc/include/mmuvar.h
+++ b/sys/powerpc/include/mmuvar.h
@@ -60,7 +60,7 @@ typedef       void    (*pmap_enter_object_t)(pmap_t, 
vm_offset_t, vm_offset_t,
 typedef        void    (*pmap_enter_quick_t)(pmap_t, vm_offset_t, vm_page_t, 
vm_prot_t);
 typedef        vm_paddr_t      (*pmap_extract_t)(pmap_t, vm_offset_t);
 typedef        vm_page_t       (*pmap_extract_and_hold_t)(pmap_t, vm_offset_t, 
vm_prot_t);
-typedef        void    (*pmap_growkernel_t)(vm_offset_t);
+typedef        int     (*pmap_growkernel_nopanic_t)(vm_offset_t);
 typedef        void    (*pmap_init_t)(void);
 typedef        bool    (*pmap_is_modified_t)(vm_page_t);
 typedef        bool    (*pmap_is_prefaultable_t)(pmap_t, vm_offset_t);
@@ -130,7 +130,7 @@ struct pmap_funcs {
        pmap_enter_quick_t      enter_quick;
        pmap_extract_t  extract;
        pmap_extract_and_hold_t extract_and_hold;
-       pmap_growkernel_t       growkernel;
+       pmap_growkernel_nopanic_t       growkernel_nopanic;
        pmap_init_t     init;
        pmap_is_modified_t      is_modified;
        pmap_is_prefaultable_t  is_prefaultable;
diff --git a/sys/powerpc/powerpc/pmap_dispatch.c 
b/sys/powerpc/powerpc/pmap_dispatch.c
index c87e65c5b23e..95806377c03d 100644
--- a/sys/powerpc/powerpc/pmap_dispatch.c
+++ b/sys/powerpc/powerpc/pmap_dispatch.c
@@ -54,6 +54,7 @@
 #include <vm/vm.h>
 #include <vm/vm_extern.h>
 #include <vm/vm_page.h>
+#include <vm/vm_param.h>
 
 #include <machine/dump.h>
 #include <machine/ifunc.h>
@@ -85,6 +86,11 @@ int superpages_enabled = 1;
 SYSCTL_INT(_vm_pmap, OID_AUTO, superpages_enabled, CTLFLAG_RDTUN,
     &superpages_enabled, 0, "Enable support for transparent superpages");
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 #ifdef AIM
 int
 pvo_vaddr_compare(struct pvo_entry *a, struct pvo_entry *b)
@@ -161,7 +167,7 @@ DEFINE_PMAP_IFUNC(void, copy_page, (vm_page_t, vm_page_t));
 DEFINE_PMAP_IFUNC(void, copy_pages,
     (vm_page_t ma[], vm_offset_t a_offset, vm_page_t mb[],
     vm_offset_t b_offset, int xfersize));
-DEFINE_PMAP_IFUNC(void, growkernel, (vm_offset_t));
+DEFINE_PMAP_IFUNC(int, growkernel_nopanic, (vm_offset_t));
 DEFINE_PMAP_IFUNC(void, init, (void));
 DEFINE_PMAP_IFUNC(vm_offset_t, map, (vm_offset_t *, vm_paddr_t, vm_paddr_t, 
int));
 DEFINE_PMAP_IFUNC(int, pinit, (pmap_t));
@@ -259,3 +265,14 @@ pmap_active_cpus(pmap_t pmap, cpuset_t *res)
 {
        *res = pmap->pm_active;
 }
+
+int
+pmap_growkernel(vm_offset_t addr)
+{
+       int rv;
+
+       rv = pmap_growkernel_nopanic(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
+}
diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c
index f756e98335f3..5d15bd671285 100644
--- a/sys/riscv/riscv/pmap.c
+++ b/sys/riscv/riscv/pmap.c
@@ -241,6 +241,11 @@ vm_paddr_t dmap_phys_base; /* The start of the dmap region 
*/
 vm_paddr_t dmap_phys_max;      /* The limit of the dmap region */
 vm_offset_t dmap_max_addr;     /* The virtual address limit of the dmap */
 
+static int pmap_growkernel_panic = 0;
+SYSCTL_INT(_vm_pmap, OID_AUTO, growkernel_panic, CTLFLAG_RDTUN,
+    &pmap_growkernel_panic, 0,
+    "panic on failure to allocate kernel page table page");
+
 /* This code assumes all L1 DMAP entries will be used */
 CTASSERT((DMAP_MIN_ADDRESS  & ~L1_OFFSET) == DMAP_MIN_ADDRESS);
 CTASSERT((DMAP_MAX_ADDRESS  & ~L1_OFFSET) == DMAP_MAX_ADDRESS);
@@ -1873,8 +1878,8 @@ SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG | 
CTLFLAG_RD | CTLFLAG_MPSAFE,
 /*
  * grow the number of kernel page table entries, if needed
  */
-void
-pmap_growkernel(vm_offset_t addr)
+static int
+pmap_growkernel_nopanic(vm_offset_t addr)
 {
        vm_paddr_t paddr;
        vm_page_t nkpg;
@@ -1894,7 +1899,8 @@ pmap_growkernel(vm_offset_t addr)
                        nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                            VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                        if (nkpg == NULL)
-                               panic("%s: no memory to grow kernel", __func__);
+                               return (KERN_RESOURCE_SHORTAGE);
+
                        nkpg->pindex = pmap_l1_pindex(kernel_vm_end);
                        paddr = VM_PAGE_TO_PHYS(nkpg);
 
@@ -1920,7 +1926,7 @@ pmap_growkernel(vm_offset_t addr)
                nkpg = vm_page_alloc_noobj(VM_ALLOC_INTERRUPT |
                    VM_ALLOC_NOFREE | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                if (nkpg == NULL)
-                       panic("%s: no memory to grow kernel", __func__);
+                       return (KERN_RESOURCE_SHORTAGE);
                nkpg->pindex = pmap_l2_pindex(kernel_vm_end);
                paddr = VM_PAGE_TO_PHYS(nkpg);
 
@@ -1937,6 +1943,19 @@ pmap_growkernel(vm_offset_t addr)
                        break;                       
                }
        }
+
+       return (KERN_SUCCESS);
+}
+
+int
+pmap_growkernel(vm_offset_t addr)
+{
+       int rv;
+
+       rv = pmap_growkernel_nopanic(addr);
+       if (rv != KERN_SUCCESS && pmap_growkernel_panic)
+               panic("pmap_growkernel: no memory to grow kernel");
+       return (rv);
 }
 
 /***************************************************
diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
index 9101201287b2..62da6a5e7ff4 100644
--- a/sys/vm/pmap.h
+++ b/sys/vm/pmap.h
@@ -136,7 +136,7 @@ void                 pmap_enter_quick(pmap_t pmap, 
vm_offset_t va, vm_page_t m,
 vm_paddr_t      pmap_extract(pmap_t pmap, vm_offset_t va);
 vm_page_t       pmap_extract_and_hold(pmap_t pmap, vm_offset_t va,
                    vm_prot_t prot);
-void            pmap_growkernel(vm_offset_t);
+int             pmap_growkernel(vm_offset_t);
 void            pmap_init(void);
 bool            pmap_is_modified(vm_page_t m);
 bool            pmap_is_prefaultable(pmap_t pmap, vm_offset_t va);
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index c6182f9ce30f..6b09552c5fee 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -1711,8 +1711,13 @@ vm_map_insert1(vm_map_t map, vm_object_t object, 
vm_ooffset_t offset,
 
 charged:
        /* Expand the kernel pmap, if necessary. */
-       if (map == kernel_map && end > kernel_vm_end)
-               pmap_growkernel(end);
+       if (map == kernel_map && end > kernel_vm_end) {
+               int rv;
+
+               rv = pmap_growkernel(end);
+               if (rv != KERN_SUCCESS)
+                       return (rv);
+       }
        if (object != NULL) {
                /*
                 * OBJ_ONEMAPPING must be cleared unless this mapping

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