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| author | kbyanc <kbyanc@FreeBSD.org> | 2004-12-08 19:03:55 +0000 |
|---|---|---|
| committer | kbyanc <kbyanc@FreeBSD.org> | 2004-12-08 19:03:55 +0000 |
| commit | f947a8cc1cf9e160deab254a7ff4be233c0f56d3 (patch) | |
| tree | cc3c26c5ae16a7d5844532ea312c2e51494cdf6c /sys | |
| parent | ef8150870e5acf935d8d5a80d0e04b08a14c5c14 (diff) | |
| download | FreeBSD-src-f947a8cc1cf9e160deab254a7ff4be233c0f56d3.zip FreeBSD-src-f947a8cc1cf9e160deab254a7ff4be233c0f56d3.tar.gz | |
If the parent process has the trap bit set (i.e. a debugger had single
stepped the process to the system call), we need to clear the trap flag
from the new frame unless the debugger had set PF_FORK on the parent.
Otherwise, the child will receive a (likely unexpected) SIGTRAP when it
executes the first instruction after returning to userland.
Reviewed by: bde
MFC after: 3 days
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/i386/i386/vm_machdep.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c index 5ec833f..10e2623 100644 --- a/sys/i386/i386/vm_machdep.c +++ b/sys/i386/i386/vm_machdep.c @@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$"); #include <sys/malloc.h> #include <sys/mbuf.h> #include <sys/mutex.h> +#include <sys/pioctl.h> #include <sys/proc.h> #include <sys/sf_buf.h> #include <sys/smp.h> @@ -195,6 +196,17 @@ cpu_fork(td1, p2, td2, flags) td2->td_frame->tf_edx = 1; /* + * If the parent process has the trap bit set (i.e. a debugger had + * single stepped the process to the system call), we need to clear + * the trap flag from the new frame unless the debugger had set PF_FORK + * on the parent. Otherwise, the child will receive a (likely + * unexpected) SIGTRAP when it executes the first instruction after + * returning to userland. + */ + if ((p1->p_pfsflags & PF_FORK) == 0) + td2->td_frame->tf_eflags &= ~PSL_T; + + /* * Set registers for trampoline to user mode. Leave space for the * return address on stack. These are the kernel mode register values. */ |
