linux-toradex.git/fs/coredump.c, branch v3.12-rc2

coredump: add new %P variable in core_pattern

2013-09-11T22:59:01+00:00

Add a new %P variable to be used in core_pattern.  This variable contains
the global PID (PID in the init namespace) as %p contains the PID in the
current namespace which isn't always what we want.

The main use for this is to make it easier to handle crashes that happened
within a container.  With that new variables it's possible to have the
crashes dumped into the container or forwarded to the host with the right
PID (from the host's point of view).

Signed-off-by: Stéphane Graber 
Reported-by: Hans Feldt 
Cc: Alexander Viro 
Cc: Eric W. Biederman 
Cc: Andy Whitcroft 
Acked-by: Serge E. Hallyn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: '% at the end' shouldn't bypass core_uses_pid logic

2013-07-03T23:08:02+00:00

"goto end" should not bypass the "Backward compatibility with
core_uses_pid" code, move this label up.

While at it,

	- It is ugly to copy '|' into cn->corename and then inc
	  the pointer for argv_split().

	  Change format_corename() to increment pat_ptr instead.

	- Remove the dead "if (*pat_ptr == 0)" in format_corename(),
	  we already checked it is not zero.

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: kill call_count, add core_name_size

2013-07-03T23:08:02+00:00

Imho, "atomic_t call_count" is ugly and should die.  It buys nothing and
in fact it can grow more than necessary, expand doesn't check if it was
already incremented by another task.

Kill it, and introduce "static int core_name_size" updated by
expand_corename().  This is obviously racy too but harmless, and
core_name_size never grows for no reason.

We do not bother to to calculate the "right" new size, we simply do
kmalloc(size_we_need) and use ksize() to rely on kmalloc_index's decision.

Finally change format_corename() to use expand_corename(), krealloc(NULL)
is fine.

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: kill cn_escape(), introduce cn_esc_printf()

2013-07-03T23:08:02+00:00

The usage of cn_escape() looks really annoying, imho this sequence needs a
wrapper.  And it is buggy.  If cn_printf() does expand_corename()
cn_escape() writes to the freed memory.

Introduce cn_esc_printf() which hopefully does this all right.  It records
the index before cn_vprintf(), not "char *" which is no longer valid (in
general) after krealloc().

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: cn_vprintf() has no reason to call vsnprintf() twice

2013-07-03T23:08:02+00:00

cn_vprintf() looks really overcomplicated and sub-optimal.  We do not need
vsnprintf(NULL) to calculate the size we need, we can simply try to print
into the current buffer and expand/retry only if necessary.

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: introduce cn_vprintf()

2013-07-03T23:08:02+00:00

Turn cn_printf(...) into cn_vprintf(va_list args), reintroduce
cn_printf() as a trivial wrapper.

This simplifies the next change and cn_vprintf() will have more
callers.

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump: format_corename() can leak cn->corename

2013-07-03T23:08:02+00:00

do_coredump() assumes that format_corename() can only fail if
expand_corename() fails and frees cn->corename.  This is not true, for
example cn_print_exe_file() can fail and in this case nobody frees
cn->corename.

Change do_coredump() to always do kfree(cn->corename) after it calls
format_corename() (NULL is fine), change expand_corename() to do nothing
if kmalloc() fails.

Signed-off-by: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Colin Walters 
Cc: Denys Vlasenko 
Cc: Jiri Slaby 
Cc: Lennart Poettering 
Cc: Lucas De Marchi 
Acked-by: Neil Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

do_coredump(): don't wait for thaw if coredump has already been interrupted

2013-05-04T18:45:54+00:00

Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-05-02T00:51:54+00:00

Pull VFS updates from Al Viro,

Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).

7kloc removed.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
  don't bother with deferred freeing of fdtables
  proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
  proc: Make the PROC_I() and PDE() macros internal to procfs
  proc: Supply a function to remove a proc entry by PDE
  take cgroup_open() and cpuset_open() to fs/proc/base.c
  ppc: Clean up scanlog
  ppc: Clean up rtas_flash driver somewhat
  hostap: proc: Use remove_proc_subtree()
  drm: proc: Use remove_proc_subtree()
  drm: proc: Use minor->index to label things, not PDE->name
  drm: Constify drm_proc_list[]
  zoran: Don't print proc_dir_entry data in debug
  reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
  proc: Supply an accessor for getting the data from a PDE's parent
  airo: Use remove_proc_subtree()
  rtl8192u: Don't need to save device proc dir PDE
  rtl8187se: Use a dir under /proc/net/r8180/
  proc: Add proc_mkdir_data()
  proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
  proc: Move PDE_NET() to fs/proc/proc_net.c
  ...

coredump: change wait_for_dump_helpers() to use wait_event_interruptible()

2013-05-01T00:04:06+00:00

wait_for_dump_helpers() calls wake_up/kill_fasync from inside the
wait_event-like loop.  This is not needed and in fact this is not
strictly correct, we can/should do this only once after we change
pipe->writers.  We could even check if it becomes zero.

Change this code to use use wait_event_interruptible(), this can also
help to make this wait freezable.

With this patch we check pipe->readers without pipe_lock(), this is
fine.  Once we see pipe->readers == 1 we know that the handler
decremented the counter, this is all we need.

Signed-off-by: Oleg Nesterov 
Acked-by: Mandeep Singh Baines 
Cc: Neil Horman 
Cc: "Rafael J. Wysocki" 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds