linux-toradex.git/fs/exec.c, branch v2.6.18

[PATCH] fix up lockdep trace in fs/exec.c

2006-08-27T18:01:32+00:00

This fixes the locking error noticed by lockdep:

  =============================================
  [ INFO: possible recursive locking detected ]
  ---------------------------------------------
  init/1 is trying to acquire lock:
   (&sighand->siglock){....}, at: [] flush_old_exec+0x3ae/0x859

  but task is already holding lock:
   (&sighand->siglock){....}, at: [] flush_old_exec+0x39e/0x859

  other info that might help us debug this:
  2 locks held by init/1:
   #0:  (tasklist_lock){..--}, at: [] flush_old_exec+0x38e/0x859
   #1:  (&sighand->siglock){....}, at: [] flush_old_exec+0x39e/0x859

  stack backtrace:
   [] show_trace_log_lvl+0x54/0xfd
   [] show_trace+0xd/0x10
   [] dump_stack+0x19/0x1b
   [] __lock_acquire+0x773/0x997
   [] lock_acquire+0x4b/0x6c
   [] _spin_lock+0x19/0x28
   [] flush_old_exec+0x3ae/0x859
   [] load_elf_binary+0x4aa/0x1628
   [] search_binary_handler+0xa7/0x24e
   [] do_execve+0x15b/0x1f9
   [] sys_execve+0x29/0x4d
   [] syscall_call+0x7/0xb

Signed-off-by: Arjan van de Ven 
Signed-off-by: Dave Jones 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

VFS: Remove redundant open-coded mode bit checks in open_exec().

2006-08-24T19:55:16+00:00

The check in open_exec() for inode->i_mode & 0111 has been made
redundant by the fix to permission().

Signed-off-by: Trond Myklebust 
(cherry picked from 1d3741c5d991686699f100b65b9956f7ee7ae0ae commit)

VFS: Remove redundant open-coded mode bit check in prepare_binfmt().

2006-08-24T19:55:06+00:00

The check in prepare_binfmt() for inode->i_mode & 0111 is redundant,
since open_exec() will already have done that.

Signed-off-by: Trond Myklebust 
(cherry picked from 822dec482ced07af32c378cd936d77345786572b commit)

Remove obsolete #include

2006-06-30T17:25:36+00:00

Signed-off-by: Jörn Engel 
Signed-off-by: Adrian Bunk

[PATCH] coredump: shutdown current process first

2006-06-26T16:58:27+00:00

This patch optimizes zap_threads() for the case when there are no ->mm
users except the current's thread group.  In that case we can avoid
'for_each_process()' loop.

It also adds a useful invariant: SIGNAL_GROUP_EXIT (if checked under
->siglock) always implies that all threads (except may be current) have
pending SIGKILL.

Signed-off-by: Oleg Nesterov 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] coredump: some code relocations

2006-06-26T16:58:27+00:00

This is a preparation for the next patch.  No functional changes.
Basically, this patch moves '->flags & SIGNAL_GROUP_EXIT' check into
zap_threads(), and 'complete(vfork_done)' into coredump_wait outside of
->mmap_sem protected area.

Signed-off-by: Oleg Nesterov 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] coredump: don't take tasklist_lock

2006-06-26T16:58:27+00:00

This patch removes tasklist_lock from zap_threads().
This is safe wrt:

	do_exit:
		The caller holds mm->mmap_sem. This means that task which
		shares the same ->mm can't pass exit_mm(), so it can't be
		unhashed from init_task.tasks or ->thread_group lists.

	fork:
		None of sub-threads can fork after zap_process(leader). All
		processes which were created before this point should be
		visible to zap_threads() because copy_process() adds the new
		process to the tail of init_task.tasks list, and ->siglock
		lock/unlock provides a memory barrier.

	de_thread:
		It does list_replace_rcu(&leader->tasks, ¤t->tasks).
		So zap_threads() will see either old or new leader, it does
		not matter. However, it can change p->sighand, so we should
		use lock_task_sighand() in zap_process().

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] coredump: kill ptrace related stuff

2006-06-26T16:58:27+00:00

With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to
the thread group.  This means that a TASK_TRACED task

	1. Will be awakened by signal_wake_up(1)

	2. Can't sleep again via ptrace_notify()

	3. Can't go to do_signal_stop() after return
	   from ptrace_stop() in get_signal_to_deliver()

So we can remove all ptrace related stuff from coredump path.

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] coredump: speedup SIGKILL sending

2006-06-26T16:58:27+00:00

With this patch a thread group is killed atomically under ->siglock.  This is
faster because we can use sigaddset() instead of force_sig_info() and this is
used in further patches.

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Acked-by: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] coredump: optimize ->mm users traversal

2006-06-26T16:58:26+00:00

zap_threads() iterates over all threads to find those ones which share
current->mm.  All threads in the thread group share the same ->mm, so we can
skip entire thread group if it has another ->mm.

This patch shifts the killing of thread group into the newly added
zap_process() function.  This looks as unnecessary complication, but it is
used in further patches.

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Acked-by: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds