Subject: + exit-call-disassociate_ctty-before-exit_task_namespaces.patch added to -mm tree
To: oleg@xxxxxxxxxx,avagin@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,jdike@xxxxxxxxxxx,mingo@xxxxxxx,peter@xxxxxxxxxxxxxxxxxx,sreeharsha@xxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 17 Mar 2014 15:30:27 -0700
The patch titled
Subject: exit: call disassociate_ctty() before exit_task_namespaces()
has been added to the -mm tree. Its filename is
exit-call-disassociate_ctty-before-exit_task_namespaces.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/exit-call-disassociate_ctty-before-exit_task_namespaces.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/exit-call-disassociate_ctty-before-exit_task_namespaces.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: exit: call disassociate_ctty() before exit_task_namespaces()
8aac62706ada ("move exit_task_namespaces() outside of exit_notify()")
breaks pppd and the exiting service crashes the kernel:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa06985a3>] ppp_register_channel+0x13/0x20 [ppp_generic]
...
Call Trace:
[<ffffffffa06ab2ab>] ? ppp_asynctty_open+0x12b/0x170 [ppp_async]
[<ffffffff812ec907>] ? tty_ldisc_open.isra.2+0x27/0x60
[<ffffffff812ed1d3>] ? tty_ldisc_hangup+0x1e3/0x220
[<ffffffff812e4614>] ? __tty_hangup+0x2c4/0x440
[<ffffffff812e56a1>] ? disassociate_ctty+0x61/0x270
[<ffffffff810483c2>] ? do_exit+0x7f2/0xa50
ppp_register_channel() needs ->net_ns and current->nsproxy == NULL.
Move disassociate_ctty() before exit_task_namespaces(), it doesn't make
sense to delay it after perf_event_exit_task() or cgroup_exit().
This also allows to use task_work_add() inside the (nontrivial) code
paths in disassociate_ctty().
Investigated by Peter Hurley.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reported-by: Sree Harsha Totakura <sreeharsha@xxxxxxxxxxx>
Cc: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Cc: Sree Harsha Totakura <sreeharsha@xxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Jeff Dike <jdike@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Andrey Vagin <avagin@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [v3.10+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff -puN kernel/exit.c~exit-call-disassociate_ctty-before-exit_task_namespaces kernel/exit.c
--- a/kernel/exit.c~exit-call-disassociate_ctty-before-exit_task_namespaces
+++ a/kernel/exit.c
@@ -784,6 +784,8 @@ void do_exit(long code)
exit_shm(tsk);
exit_files(tsk);
exit_fs(tsk);
+ if (group_dead)
+ disassociate_ctty(1);
exit_task_namespaces(tsk);
exit_task_work(tsk);
check_stack_usage();
@@ -799,13 +801,9 @@ void do_exit(long code)
cgroup_exit(tsk, 1);
- if (group_dead)
- disassociate_ctty(1);
-
module_put(task_thread_info(tsk)->exec_domain->module);
proc_exit_connector(tsk);
-
/*
* FIXME: do that only when needed, using sched_exit tracepoint
*/
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
kthread-ensure-locality-of-task_struct-allocations.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags-ignore-madv_hugepage-on-s390-to-prevent-sigsegv-in-qemu.patch
mm-thp-add-vm_init_def_mask-and-prctl_thp_disable.patch
exec-kill-the-unnecessary-mm-def_flags-setting-in-load_elf_binary.patch
mm-per-thread-vma-caching.patch
mm-per-thread-vma-caching-fix-4.patch
mm-per-thread-vma-caching-fix-6.patch
mm-per-thread-vma-caching-fix-6-fix.patch
fork-collapse-copy_flags-into-copy_process.patch
mm-mempolicy-rename-slab_node-for-clarity.patch
mm-mempolicy-remove-per-process-flag.patch
res_counter-remove-interface-for-locked-charging-and-uncharging.patch
exit-call-disassociate_ctty-before-exit_task_namespaces.patch
exit-move-check_stack_usage-to-the-end-of-do_exit.patch
exitc-call-proc_exit_connector-after-exit_state-is-set.patch
wait-fix-reparent_leader-vs-exit_dead-exit_zombie-race.patch
wait-introduce-exit_trace-to-avoid-the-racy-exit_dead-exit_zombie-transition.patch
wait-use-exit_trace-only-if-thread_group_leaderzombie.patch
wait-completely-ignore-the-exit_dead-tasks.patch
wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch
wait-wstoppedwcontinued-hangs-if-a-zombie-child-is-traced-by-real_parent.patch
wait-wstoppedwcontinued-doesnt-work-if-a-zombie-leader-is-traced-by-another-process.patch
linux-next.patch
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