The patch titled
Subject: ptrace_attach: shift send(SIGSTOP) into ptrace_set_stopped()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: ptrace_attach: shift send(SIGSTOP) into ptrace_set_stopped()
Date: Mon, 22 Jan 2024 18:16:31 +0100
Turn send_sig_info(SIGSTOP) into send_signal_locked(SIGSTOP) and move it
from ptrace_attach() to ptrace_set_stopped().
This looks more logical and avoids lock(siglock) right after unlock().
Link: https://lkml.kernel.org/r/20240122171631.GA29844@xxxxxxxxxx
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/ptrace.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
--- a/kernel/ptrace.c~ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped
+++ a/kernel/ptrace.c
@@ -375,10 +375,13 @@ static int check_ptrace_options(unsigned
return 0;
}
-static inline void ptrace_set_stopped(struct task_struct *task)
+static inline void ptrace_set_stopped(struct task_struct *task, bool seize)
{
guard(spinlock)(&task->sighand->siglock);
+ /* SEIZE doesn't trap tracee on attach */
+ if (!seize)
+ send_signal_locked(SIGSTOP, SEND_SIG_PRIV, task, PIDTYPE_PID);
/*
* If the task is already STOPPED, set JOBCTL_TRAP_STOP and
* TRAPPING, and kick it so that it transits to TRACED. TRAPPING
@@ -457,14 +460,8 @@ static int ptrace_attach(struct task_str
return -EPERM;
task->ptrace = flags;
-
ptrace_link(task, current);
-
- /* SEIZE doesn't trap tracee on attach */
- if (!seize)
- send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
-
- ptrace_set_stopped(task);
+ ptrace_set_stopped(task, seize);
}
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
getrusage-move-thread_group_cputime_adjusted-outside-of-lock_task_sighand.patch
getrusage-use-sig-stats_lock.patch
ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped.patch
