git: 800da341bc4a - main - thread: Simplify sanitizer integration with thread creation
Date: Mon, 22 Apr 2024 15:54:27 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=800da341bc4a35f4b4d82d104b130825d9a42ffa
commit 800da341bc4a35f4b4d82d104b130825d9a42ffa
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2024-04-22 15:43:17 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-04-22 15:46:59 +0000
thread: Simplify sanitizer integration with thread creation
fork() may allocate a new thread in one of two ways: from UMA, or cached
in a freed proc that was just allocated from UMA. In either case, KASAN
and KMSAN need to initialize some state; in particular they need to
initialize the shadow mapping of the new thread's stack.
This is done differently between KASAN and KMSAN, which is confusing.
This patch improves things a bit:
- Add a new thread_recycle() function, which moves all kernel stack
handling out of kern_fork.c, since it doesn't really belong there.
- Then, thread_alloc_stack() has only one local caller, so just inline
it.
- Avoid redundant shadow stack initialization: thread_alloc()
initializes the KMSAN shadow stack (via kmsan_thread_alloc()) even
through vm_thread_new() already did that.
- Add kasan_thread_alloc(), for consistency with kmsan_thread_alloc().
No functional change intended.
Reviewed by: khng
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D44891
---
sys/kern/kern_fork.c | 17 +++--------------
sys/kern/kern_thread.c | 20 ++++++++++++--------
sys/kern/subr_asan.c | 10 ++++++++++
sys/sys/asan.h | 4 ++++
sys/sys/proc.h | 2 +-
sys/vm/vm_glue.c | 9 ++++-----
6 files changed, 34 insertions(+), 28 deletions(-)
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index d0044dfc19a0..41f6a76c4fa1 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -40,7 +40,6 @@
#include <sys/param.h>
#include <sys/systm.h>
-#include <sys/asan.h>
#include <sys/bitstring.h>
#include <sys/sysproto.h>
#include <sys/eventhandler.h>
@@ -1019,19 +1018,9 @@ fork1(struct thread *td, struct fork_req *fr)
}
proc_linkup(newproc, td2);
} else {
- kmsan_thread_alloc(td2);
- if (td2->td_kstack == 0 || td2->td_kstack_pages != pages) {
- if (td2->td_kstack != 0)
- vm_thread_dispose(td2);
- if (!thread_alloc_stack(td2, pages)) {
- error = ENOMEM;
- goto fail2;
- }
- } else {
- kasan_mark((void *)td2->td_kstack,
- ptoa(td2->td_kstack_pages),
- ptoa(td2->td_kstack_pages), 0);
- }
+ error = thread_recycle(td2, pages);
+ if (error != 0)
+ goto fail2;
}
if ((flags & RFMEM) == 0) {
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index 0bcd5c2f2add..725791769ac3 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -798,6 +798,7 @@ thread_alloc(int pages)
}
td->td_tid = tid;
bzero(&td->td_sa.args, sizeof(td->td_sa.args));
+ kasan_thread_alloc(td);
kmsan_thread_alloc(td);
cpu_thread_alloc(td);
EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
@@ -805,15 +806,18 @@ thread_alloc(int pages)
}
int
-thread_alloc_stack(struct thread *td, int pages)
+thread_recycle(struct thread *td, int pages)
{
-
- KASSERT(td->td_kstack == 0,
- ("thread_alloc_stack called on a thread with kstack"));
- if (!vm_thread_new(td, pages))
- return (0);
- cpu_thread_alloc(td);
- return (1);
+ if (td->td_kstack == 0 || td->td_kstack_pages != pages) {
+ if (td->td_kstack != 0)
+ vm_thread_dispose(td);
+ if (!vm_thread_new(td, pages))
+ return (ENOMEM);
+ cpu_thread_alloc(td);
+ }
+ kasan_thread_alloc(td);
+ kmsan_thread_alloc(td);
+ return (0);
}
/*
diff --git a/sys/kern/subr_asan.c b/sys/kern/subr_asan.c
index c3664d9cf6c2..75d9e75c531a 100644
--- a/sys/kern/subr_asan.c
+++ b/sys/kern/subr_asan.c
@@ -39,6 +39,7 @@ __KERNEL_RCSID(0, "$NetBSD: subr_asan.c,v 1.26 2020/09/10 14:10:46 maxv Exp $");
#include <sys/systm.h>
#include <sys/asan.h>
#include <sys/kernel.h>
+#include <sys/proc.h>
#include <sys/stack.h>
#include <sys/sysctl.h>
@@ -294,6 +295,15 @@ kasan_mark(const void *addr, size_t size, size_t redzsize, uint8_t code)
}
}
+void
+kasan_thread_alloc(struct thread *td)
+{
+ if (td->td_kstack != 0) {
+ kasan_mark((void *)td->td_kstack, ptoa(td->td_kstack_pages),
+ ptoa(td->td_kstack_pages), 0);
+ }
+}
+
/* -------------------------------------------------------------------------- */
#define ADDR_CROSSES_SCALE_BOUNDARY(addr, size) \
diff --git a/sys/sys/asan.h b/sys/sys/asan.h
index a3becdef5f57..6a01d0531725 100644
--- a/sys/sys/asan.h
+++ b/sys/sys/asan.h
@@ -53,14 +53,18 @@
#define KASAN_KSTACK_FREED 0xFE
#define KASAN_EXEC_ARGS_FREED 0xFF
+struct thread;
+
void kasan_init(void);
void kasan_init_early(vm_offset_t, size_t);
void kasan_shadow_map(vm_offset_t, size_t);
void kasan_mark(const void *, size_t, size_t, uint8_t);
+void kasan_thread_alloc(struct thread *);
#else /* KASAN */
#define kasan_init()
#define kasan_shadow_map(a, s)
#define kasan_mark(p, s, l, c)
+#define kasan_thread_alloc(t)
#endif /* !KASAN */
#endif /* !_SYS_ASAN_H_ */
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 33b836f4150e..1b542d1374b4 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1262,7 +1262,6 @@ void cpu_thread_free(struct thread *);
void cpu_thread_swapin(struct thread *);
void cpu_thread_swapout(struct thread *);
struct thread *thread_alloc(int pages);
-int thread_alloc_stack(struct thread *, int pages);
int thread_check_susp(struct thread *td, bool sleep);
void thread_cow_get_proc(struct thread *newtd, struct proc *p);
void thread_cow_get(struct thread *newtd, struct thread *td);
@@ -1275,6 +1274,7 @@ void thread_exit(void) __dead2;
void thread_free(struct thread *td);
void thread_link(struct thread *td, struct proc *p);
void thread_reap_barrier(void);
+int thread_recycle(struct thread *, int pages);
int thread_single(struct proc *p, int how);
void thread_single_end(struct proc *p, int how);
void thread_stash(struct thread *td);
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
index 4292a7533503..f9235fe03fab 100644
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@@ -543,8 +543,6 @@ vm_thread_new(struct thread *td, int pages)
td->td_kstack = ks;
td->td_kstack_pages = pages;
td->td_kstack_domain = ks_domain;
- kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0);
- kmsan_mark((void *)ks, ptoa(pages), KMSAN_STATE_UNINIT);
return (1);
}
@@ -562,11 +560,12 @@ vm_thread_dispose(struct thread *td)
td->td_kstack = 0;
td->td_kstack_pages = 0;
td->td_kstack_domain = MAXMEMDOM;
- kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
- if (pages == kstack_pages)
+ if (pages == kstack_pages) {
+ kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
uma_zfree(kstack_cache, (void *)ks);
- else
+ } else {
vm_thread_stack_dispose(ks, pages);
+ }
}
/*