Roland McGrath wrote:It took some further time to understand what is closer to the source of the problem. Previously I had just bisected backwards until ptrace started working again because I knew it had broken between 2.6.14 and 2.6.21. The test case provided in the patch I submitted either always fails or always succeeds. I had a particular machine and file system that it always failed on. I reduced the configuration to UP i386 with a file system that was using full kernel auditing. It turns out that it is the _TIF_SYSCALL_AUDIT interaction in entry.S is more likely the culprit here. This flag was getting turned on as a result of using kernel/user space auditing. I found that you can turn off CONFIG_AUDIT and use the patch below to "simulate" the same circumstance. Then you should be able to observe the same failure I saw directly with a vanilla 2.6.21 i386 kernel. diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S diff --git a/kernel/fork.c b/kernel/fork.c index 6af959c..fb47ab9 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1154,6 +1154,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, #ifdef TIF_SYSCALL_EMU clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); #endif + /* HACK to always turn on syscall auditing */ + set_tsk_thread_flag(p, TIF_SYSCALL_AUDIT); + /* end HACK to simulate auditing */ /* Our parent execution domain becomes current domain These must match for thread signalling to apply */ Let me know if you need further details, and it certainly means some further testing is in order against your newer patch. I am also interested in what test cases fail that you mentioned in your original e-mail on this topic. Thanks, Jason. --
| Amit K. Arora | [RFC] Heads up on sys_fallocate() |
| Greg KH | [GIT PATCH] driver core patches against 2.6.24 |
| Linus Torvalds | Linux 2.6.25-rc4 |
| Greg KH | Linux 2.6.25.10 |
git: | |
| Gerrit Renker | [PATCH 15/37] dccp: Set per-connection CCIDs via socket options |
| David Miller | Re: [PATCH] pkt_sched: Destroy gen estimators under rtnl_lock(). |
| David Miller | [GIT]: Networking |
| Ilpo Järvinen | Re: Strange Application bug, race in MSG_PEEK complaints (was: Bug#513695: fetchma... |
