The patch titled
Only send pdeath_signal when getppid changes
has been added to the -mm tree. Its filename is
only-send-pdeath_signal-when-getppid-changes.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Only send pdeath_signal when getppid changes
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Currently each thread can requrest to be notified when it's parent terminates,
and receive a thread specific signal when that occurs. That we set this on a
per thread granularity and then send it to the whole thread group seems silly,
but whatever.
Currently we send a signal when the results of getppid don't change if our
parent thread dies and we are reparented to a different thread. This seems
counterintuitive to what I would expect when programming in user space and is
a major maitenance issue to continue doing.
The only users I recall using this have non threaded parents and pdeath_signal
predates CLONE_THREAD so arguably this code has been broken with threaded
parents since the day CLONE_THREAD was introduced and no one ever screamed
loudly enough to get it fixed.
So this patch fixes the pdeath_signal behaviour only sending a signal when the
results of getppid would change.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Albert Cahalan <acahalan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff -puN kernel/exit.c~only-send-pdeath_signal-when-getppid-changes kernel/exit.c
--- a/kernel/exit.c~only-send-pdeath_signal-when-getppid-changes
+++ a/kernel/exit.c
@@ -598,10 +598,6 @@ choose_new_parent(struct task_struct *p,
static void
reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
{
- if (p->pdeath_signal)
- /* We already hold the tasklist_lock here. */
- group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
-
/* Move the child from its dying parent to the new one. */
if (unlikely(traced)) {
/* Preserve ptrace links if someone else is tracing this child. */
@@ -637,6 +633,10 @@ reparent_thread(struct task_struct *p, s
if (p->exit_signal != -1)
p->exit_signal = SIGCHLD;
+ if (p->pdeath_signal)
+ /* We already hold the tasklist_lock here. */
+ group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+
/* If we'd notified the old parent about this child's death,
* also notify the new parent.
*/
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
powerpc-rtas-msi-support.patch
fix-i-oat-for-kexec.patch
fix-x86_64-mm-relocatable-kernel-support.patch
i386-irq-kill-irq-compression.patch
i386-relocate-vdso-elf-headers-to-match-mapped-location-with-compat_vdso.patch
i386-make-compat_vdso-runtime-selectable.patch
clone-flag-clone_parent_tidptr-leaves-invalid-results-in-memory.patch
allow-access-to-proc-pid-fd-after-setuid.patch
merge-sys_clone-sys_unshare-nsproxy-and-namespace.patch
fix-race-between-proc_get_inode-and-remove_proc_entry.patch
fix-race-between-proc_readdir-and-remove_proc_entry.patch
procfs-reorder-struct-pid_dentry-to-save-space-on-64bit-archs-and-constify-them.patch
tty-remove-unnecessary-export-of-proc_clear_tty.patch
tty-simplify-calling-of-put_pid.patch
tty-introduce-no_tty-and-use-it-in-selinux.patch
tty-in-tiocsctty-when-we-steal-a-tty-hang-it-up.patch
tty-in-tiocsctty-when-we-steal-a-tty-hang-it-up-fix.patch
clean-up-elf-note-generation.patch
remove-hardcoding-of-hard_smp_processor_id-on-up.patch
use-the-apic-to-determine-the-hardware-processor-id-i386.patch
use-the-apic-to-determine-the-hardware-processor-id-x86_64.patch
always-ask-the-hardware-to-obtain-hardware-processor-id-ia64.patch
only-send-pdeath_signal-when-getppid-changes.patch
edac-k8-driver-coding-tidy.patch
statically-initialize-struct-pid-for-swapper.patch
explicitly-set-pgid-and-sid-of-init-process.patch
use-struct-pid-parameter-in-copy_process.patch
use-task_pgrp-task_session-in-copy_process.patch
kill-unused-sesssion-and-group-values-in-rocket-driver.patch
fix-some-coding-style-errors-in-autofs.patch
replace-pid_t-in-autofs-with-struct-pid-reference.patch
dont-init-pgrp-and-__session-in-init_signals.patch
vdso-print-fatal-signals-use-ctl_unnumbered.patch
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