The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=f0592b3c8dd8e172f0e7165c11371108d4d8838d
commit f0592b3c8dd8e172f0e7165c11371108d4d8838d
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2022-12-01 00:29:35 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2022-12-22 21:11:35 +0000
Add a thread debugging flag TDB_BOUNDARY
It indicates to a debugger that the thread is stopped at the
kernel->user exit path.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D37590
---
sys/kern/kern_sig.c | 5 ++++-
sys/kern/subr_syscall.c | 11 ++++++++---
sys/sys/proc.h | 3 ++-
3 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 11c0334181e1..eea624019fff 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -279,7 +279,7 @@ static void
ast_sig(struct thread *td, int tda)
{
struct proc *p;
- int sig;
+ int old_boundary, sig;
bool resched_sigs;
p = td->td_proc;
@@ -321,12 +321,15 @@ ast_sig(struct thread *td, int tda)
!SIGISEMPTY(p->p_siglist)) {
sigfastblock_fetch(td);
PROC_LOCK(p);
+ old_boundary = ~TDB_BOUNDARY | (td->td_dbgflags & TDB_BOUNDARY);
+ td->td_dbgflags |= TDB_BOUNDARY;
mtx_lock(&p->p_sigacts->ps_mtx);
while ((sig = cursig(td)) != 0) {
KASSERT(sig >= 0, ("sig %d", sig));
postsig(sig);
}
mtx_unlock(&p->p_sigacts->ps_mtx);
+ td->td_dbgflags &= old_boundary;
PROC_UNLOCK(p);
resched_sigs = true;
} else {
diff --git a/sys/kern/subr_syscall.c b/sys/kern/subr_syscall.c
index 33dd50d3d50a..36830a13e596 100644
--- a/sys/kern/subr_syscall.c
+++ b/sys/kern/subr_syscall.c
@@ -73,6 +73,7 @@ syscallenter(struct thread *td)
traced = (p->p_flag & P_TRACED) != 0;
if (__predict_false(traced || td->td_dbgflags & TDB_USERWR)) {
PROC_LOCK(p);
+ MPASS((td->td_dbgflags & TDB_BOUNDARY) == 0);
td->td_dbgflags &= ~TDB_USERWR;
if (traced)
td->td_dbgflags |= TDB_SCE;
@@ -201,7 +202,7 @@ syscallenter(struct thread *td)
td->td_retval[1]);
if (__predict_false(traced)) {
PROC_LOCK(p);
- td->td_dbgflags &= ~TDB_SCE;
+ td->td_dbgflags &= ~(TDB_SCE | TDB_BOUNDARY);
PROC_UNLOCK(p);
}
(p->p_sysent->sv_set_syscall_retval)(td, error);
@@ -280,9 +281,13 @@ syscallret(struct thread *td)
*/
if (traced &&
((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
- (p->p_ptevents & PTRACE_SCX) != 0))
+ (p->p_ptevents & PTRACE_SCX) != 0)) {
+ MPASS((td->td_dbgflags & TDB_BOUNDARY) == 0);
+ td->td_dbgflags |= TDB_BOUNDARY;
ptracestop(td, SIGTRAP, NULL);
- td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
+ }
+ td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK |
+ TDB_BOUNDARY);
PROC_UNLOCK(p);
}
}
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 1552da628b11..f17207d741c1 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -522,7 +522,8 @@ enum {
#define TDB_FSTP 0x00001000 /* The thread is PT_ATTACH leader */
#define TDB_STEP 0x00002000 /* (x86) PSL_T set for PT_STEP */
#define TDB_SSWITCH 0x00004000 /* Suspended in ptracestop */
-#define TDB_COREDUMPREQ 0x00008000 /* Coredump request */
+#define TDB_BOUNDARY 0x00008000 /* ptracestop() at boundary */
+#define TDB_COREDUMPREQ 0x00010000 /* Coredump request */
/*
* "Private" flags kept in td_pflags:
