1. 01 May, 2013 3 commits
    • Oleg Nesterov's avatar
      coredump: only SIGKILL should interrupt the coredumping task · 403bad72
      Oleg Nesterov authored
      
      
      There are 2 well known and ancient problems with coredump/signals, and a
      lot of related bug reports:
      
      - do_coredump() clears TIF_SIGPENDING but of course this can't help
        if, say, SIGCHLD comes after that.
      
        In this case the coredump can fail unexpectedly. See for example
        wait_for_dump_helper()->signal_pending() check but there are other
        reasons.
      
      - At the same time, dumping a huge core on the slow media can take a
        lot of time/resources and there is no way to kill the coredumping
        task reliably. In particular this is not oom_kill-friendly.
      
      This patch tries to fix the 1st problem, and makes the preparation for the
      next changes.
      
      We add the new SIGNAL_GROUP_COREDUMP flag set by zap_threads() to indicate
      that this process dumps the core.  prepare_signal() checks this flag and
      nacks any signal except SIGKILL.
      
      Note that this check tries to be conservative, in the long term we should
      probably treat the SIGNAL_GROUP_EXIT case equally but this needs more
      discussion.  See marc.info/?l=linux-kernel&m=120508897917439
      
      Notes:
      	- recalc_sigpending() doesn't check SIGNAL_GROUP_COREDUMP.
      	  The patch assumes that dump_write/etc paths should never
      	  call it, but we can change it as well.
      
      	- There is another source of TIF_SIGPENDING, freezer. This
      	  will be addressed separately.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Tested-by: default avatarMandeep Singh Baines <msb@chromium.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Neil Horman <nhorman@redhat.com>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Cc: Roland McGrath <roland@hack.frob.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      403bad72
    • Lucas De Marchi's avatar
      usermodehelper: split remaining calls to call_usermodehelper_fns() · 907ed132
      Lucas De Marchi authored
      
      
      These are the only users of call_usermodehelper_fns().  This function
      suffers from not being able to determine if the cleanup is called.  Even
      if in this places the cleanup pointer is NULL, convert them to use the
      separate call_usermodehelper_setup() + call_usermodehelper_exec()
      functions so we can remove the _fns variant.
      Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: James Morris <james.l.morris@oracle.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      907ed132
    • Lucas De Marchi's avatar
      coredump: remove trailling whitespace · fb96c475
      Lucas De Marchi authored
      
      Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: James Morris <james.l.morris@oracle.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fb96c475
  2. 28 Feb, 2013 1 commit
  3. 23 Feb, 2013 1 commit
  4. 29 Nov, 2012 1 commit
  5. 16 Oct, 2012 1 commit
    • Al Viro's avatar
      fix a leak in replace_fd() users · 45525b26
      Al Viro authored
      
      
      replace_fd() began with "eats a reference, tries to insert into
      descriptor table" semantics; at some point I'd switched it to
      much saner current behaviour ("try to insert into descriptor
      table, grabbing a new reference if inserted; caller should do
      fput() in any case"), but forgot to update the callers.
      Mea culpa...
      
      [Spotted by Pavel Roskin, who has really weird system with pipe-fed
      coredumps as part of what he considers a normal boot ;-)]
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      45525b26
  6. 05 Oct, 2012 3 commits
  7. 03 Oct, 2012 1 commit