linux-kernel - perf_event_mmap(vma) && !vma->vm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 12 Oct 2013 21:22:03 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org
Subject: perf_event_mmap(vma) && !vma->vm_mm

Hi,

I am fighting with uprobe bug, and perf_event_mmap() complicates
the problem, it is the only reason (afaics) why the forking task
can not do install_special_mapping(new_child_mm). This means that
the child should do this itself, say, from task_work_run() but
this way it can't handle the error if get_xol_area() fails, too
late to abort the already finished copy_process().

But please ignore, the only question is that I can't understand
this

	if (!vma->vm_mm) {
		name = strncpy(tmp, "[vdso]", sizeof(tmp));
		goto got_name;
	}

code in perf_event_mmap_event() and I am just curious. How it is
possible that vma->vm_mm == NULL ? perf_event_mmap(vma) is never
called with, say, vma == gate_vma. And even if it was possible
arch_vma_name() should handle this case?

Thanks,

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/