Date: Sun, 25 Jan 2026 00:24:47 +0000 From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 21dd894a5e0f - stable/15 - sys: do not allow entering vm_fault() on boot until VM is initialized Message-ID: <697562cf.8088.11c51627@gitrepo.freebsd.org>
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The branch stable/15 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=21dd894a5e0ff42f2a7f34ad2fe4e4fc06a00126 commit 21dd894a5e0ff42f2a7f34ad2fe4e4fc06a00126 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2026-01-18 21:14:59 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2026-01-25 00:23:35 +0000 sys: do not allow entering vm_fault() on boot until VM is initialized (cherry picked from commit 83d98828867591b5d842573ed6edcec7392f82df) --- sys/amd64/amd64/machdep.c | 5 +---- sys/kern/init_main.c | 12 +++++++++++- sys/vm/vm_init.c | 8 ++++++++ 3 files changed, 20 insertions(+), 5 deletions(-) diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index 2fce1a7e64b6..cae58181000f 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1518,13 +1518,11 @@ hammer_time(u_int64_t modulep, u_int64_t physfree) /* * We initialize the PCB pointer early so that exception - * handlers will work. Also set up td_critnest to short-cut - * the page fault handler. + * handlers will work. */ cpu_max_ext_state_size = sizeof(struct savefpu); set_top_of_stack_td(&thread0); thread0.td_pcb = get_pcb_td(&thread0); - thread0.td_critnest = 1; /* * The console and kdb should be initialized even earlier than here, @@ -1615,7 +1613,6 @@ hammer_time(u_int64_t modulep, u_int64_t physfree) #ifdef FDT x86_init_fdt(); #endif - thread0.td_critnest = 0; kasan_init(); kmsan_init(); diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c index 48cc9c1d95c4..4cccb2546a9a 100644 --- a/sys/kern/init_main.c +++ b/sys/kern/init_main.c @@ -104,7 +104,17 @@ void mi_startup(void); /* Should be elsewhere */ static struct session session0; static struct pgrp pgrp0; struct proc proc0; -struct thread0_storage thread0_st __aligned(32); +struct thread0_storage thread0_st __aligned(32) = { + .t0st_thread = { + /* + * thread0.td_pflags is set with TDP_NOFAULTING to + * short-cut the vm page fault handler until it is + * ready. It is cleared in vm_init() after VM + * initialization. + */ + .td_pflags = TDP_NOFAULTING, + }, +}; struct vmspace vmspace0; struct proc *initproc; diff --git a/sys/vm/vm_init.c b/sys/vm/vm_init.c index a0d3651ba266..2764b438d27b 100644 --- a/sys/vm/vm_init.c +++ b/sys/vm/vm_init.c @@ -159,6 +159,14 @@ vm_mem_init(void *dummy) pmap_init(); vm_pager_init(); + /* + * Now we can properly handle calls into vm_fault() from + * kernel page faults during initialization, typically to + * panic. Clear the nofaulting flag set for thread0 in the + * image, see kern/init_main.c + */ + curthread->td_pflags &= ~TDP_NOFAULTING; + #ifdef INVARIANTS vm_check_pagesizes(); #endifhome | help
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