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authorOleg Nesterov <oleg@redhat.com>2009-02-09 04:02:33 +0300
committerIngo Molnar <mingo@elte.hu>2009-02-11 12:32:46 +0300
commit06eb23b1ba39c61ee5d5faeb42a097635693e370 (patch)
treea06f34d6ed32521ea32641df30732d9eb9d24757
parentb52af40923fc91a12e3c7152d833e0c0c6a508f6 (diff)
downloadlinux-06eb23b1ba39c61ee5d5faeb42a097635693e370.tar.xz
ptrace, x86: fix the usage of ptrace_fork()
I noticed by pure accident we have ptrace_fork() and friends. This was added by "x86, bts: add fork and exit handling", commit bf53de907dfdaac178c92d774aae7370d7b97d20. I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly believe this needs the fix. I think something like this program int main(void) { int pid = fork(); if (!pid) { ptrace(PTRACE_TRACEME, 0, NULL, NULL); kill(getpid(), SIGSTOP); fork(); } else { struct ptrace_bts_config bts = { .flags = PTRACE_BTS_O_ALLOC, .size = 4 * 4096, }; wait(NULL); ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK); ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts)); ptrace(PTRACE_CONT, pid, NULL, NULL); sleep(1); } return 0; } should crash the kernel. If the task is traced by its natural parent ptrace_reparented() returns 0 but we should clear ->btsxxx anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/fork.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 242a706e7721..43c039d55e95 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1093,7 +1093,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
#ifdef CONFIG_DEBUG_MUTEXES
p->blocked_on = NULL; /* not blocked yet */
#endif
- if (unlikely(ptrace_reparented(current)))
+ if (unlikely(current->ptrace))
ptrace_fork(p, clone_flags);
/* Perform scheduler related setup. Assign this task to a CPU. */