From ceca3c193e73bb409d093515fae9e5ef02ffa2de Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 26 Apr 2011 22:37:11 +0200 Subject: tile: do_hardwall_trap: do not play with task->sighand 1. do_hardwall_trap() checks ->sighand != NULL and then takes ->siglock. This is unsafe even if the task can't run (I assume it is pinned to the same CPU), its parent can reap the task and set ->sighand = NULL right after this check. Even if the compiler dosn't read ->sighand twice and this memory can't to away __group_send_sig_info() is wrong after that. Use do_send_sig_info(). 2. Send SIGILL to the thread, not to the whole process. Unless it has the handler or blocked this kills the whole thread-group as before. IIUC, different threads can be bound to different rect's. 3. Check PF_EXITING instead of ->sighand. A zombie thread can go away but its ->sighand can be !NULL. Reported-by: Matt Fleming Signed-off-by: Oleg Nesterov Signed-off-by: Chris Metcalf --- arch/tile/kernel/hardwall.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/tile') diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c index e910530436e6..3bddef710de4 100644 --- a/arch/tile/kernel/hardwall.c +++ b/arch/tile/kernel/hardwall.c @@ -268,12 +268,10 @@ void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num) found_processes = 0; list_for_each_entry(p, &rect->task_head, thread.hardwall_list) { BUG_ON(p->thread.hardwall != rect); - if (p->sighand) { + if (!(p->flags & PF_EXITING)) { found_processes = 1; pr_notice("hardwall: killing %d\n", p->pid); - spin_lock(&p->sighand->siglock); - __group_send_sig_info(info.si_signo, &info, p); - spin_unlock(&p->sighand->siglock); + do_send_sig_info(info.si_signo, &info, p, false); } } if (!found_processes) -- cgit v1.2.3