Date: Mon, 9 Jul 2012 09:24:46 +0000 (UTC) From: David Xu <davidxu@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r238287 - head/sys/kern Message-ID: <201207090924.q699OkB0007789@svn.freebsd.org>
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Author: davidxu Date: Mon Jul 9 09:24:46 2012 New Revision: 238287 URL: http://svn.freebsd.org/changeset/base/238287 Log: If you have pressed CTRL+Z and a process is suspended, then you use gdb to attach to the process, it is surprising that the process is resumed without inputting any gdb commands, however ptrace manual said: The tracing process will see the newly-traced process stop and may then control it as if it had been traced all along. But the current code does not work in this way, unless traced process received a signal later, it will continue to run as a background task. To fix this problem, just send signal SIGSTOP to the traced process after we resumed it, this works like that you are attaching to a running process, it is not perfect but better than nothing. Modified: head/sys/kern/sys_process.c Modified: head/sys/kern/sys_process.c ============================================================================== --- head/sys/kern/sys_process.c Mon Jul 9 09:11:07 2012 (r238286) +++ head/sys/kern/sys_process.c Mon Jul 9 09:24:46 2012 (r238287) @@ -635,7 +635,7 @@ kern_ptrace(struct thread *td, int req, struct iovec iov; struct uio uio; struct proc *curp, *p, *pp; - struct thread *td2 = NULL; + struct thread *td2 = NULL, *td3; struct ptrace_io_desc *piod = NULL; struct ptrace_lwpinfo *pl; int error, write, tmp, num; @@ -953,10 +953,8 @@ kern_ptrace(struct thread *td, int req, td2->td_xsig = data; if (req == PT_DETACH) { - struct thread *td3; - FOREACH_THREAD_IN_PROC(p, td3) { + FOREACH_THREAD_IN_PROC(p, td3) td3->td_dbgflags &= ~TDB_SUSPEND; - } } /* * unsuspend all threads, to not let a thread run, @@ -967,6 +965,8 @@ kern_ptrace(struct thread *td, int req, p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED); thread_unsuspend(p); PROC_SUNLOCK(p); + if (req == PT_ATTACH) + kern_psignal(p, data); } else { if (data) kern_psignal(p, data);
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