android_kernel_xiaomi_sm8350/arch/um/os-Linux
Stanislaw Gruszka 4dbed85a35 uml: stop gdb from deleting breakpoints when running UML
Sometimes when UML is debugged gdb miss breakpoints.

When process traced by gdb do fork, debugger remove breakpoints from
child address space. There is possibility to trace more than one fork,
but this not work with UML, I guess (only guess) there is a deadlock -
gdb waits for UML and UML waits for gdb.

When clone() is called with SIGCHLD and CLONE_VM flags, gdb see this
as PTRACE_EVENT_FORK not as PTRACE_EVENT_CLONE and remove breakpoints
from child and at the same time from traced process, because either
have the same address space.

Maybe it is possible to do fix in gdb, but I'm not sure if there is
easy way to find out if traced and child processes share memory. So I
do fix for UML, it simply do not call clone() with both SIGCHLD and
CLONE_VM flags together.  Additionally __WALL flag is used for
waitpid() to assure not miss clone and normal process events.

[ jdike - checkpatch fixes ]

Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-17 19:28:15 -08:00
..
drivers uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00
include
skas uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00
sys-i386 uml: style fixes in FP code 2007-10-16 09:43:07 -07:00
sys-x86_64
aio.c uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00
elf_aux.c
execvp.c
file.c uml: fix recvmsg return value checking 2007-11-14 18:45:37 -08:00
helper.c uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00
irq.c uml: eliminate SIGALRM 2007-10-16 09:43:08 -07:00
main.c uml: eliminate SIGALRM 2007-10-16 09:43:08 -07:00
Makefile
mem.c
process.c uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00
registers.c
sigio.c
signal.c uml: eliminate SIGALRM 2007-10-16 09:43:08 -07:00
start_up.c
time.c uml: after_sleep_interval should return something 2007-12-03 08:13:17 -08:00
tls.c
trap.c uml: eliminate SIGALRM 2007-10-16 09:43:08 -07:00
tty_log.c
tty.c
uaccess.c
umid.c
user_syms.c
util.c uml: stop gdb from deleting breakpoints when running UML 2007-12-17 19:28:15 -08:00