Messages in this thread Patch in this message |  | | Date | Mon, 16 Jun 2008 20:26:03 +0400 | From | Oleg Nesterov <> | Subject | [PATCH] coredump: elf_core_dump: skip kernel threads |
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linux_binfmt->core_dump() runs before the process does exit_aio(), this means that we can hit the kernel thread which shares the same ->mm. Afaics, nothing really bad can happen, but perhaps it makes sense to fix this minor bug.
It is sad we have to iterate over all threads in system and use GFP_ATOMIC. Hopefully we can kill theses ugly do_each_thread()s, but this needs some nontrivial changes in mm_struct and do_coredump.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
binfmt_elf.c | 6 ++++++ binfmt_elf_fdpic.c | 3 +++ 2 files changed, 9 insertions(+)
--- 26-rc2/fs/binfmt_elf.c~CD_SKIP_KTHREAD 2008-06-02 20:46:54.000000000 +0400 +++ 26-rc2/fs/binfmt_elf.c 2008-06-16 20:00:00.000000000 +0400 @@ -1522,6 +1522,9 @@ static int fill_note_info(struct elfhdr rcu_read_lock(); do_each_thread(g, p) if (p->mm == dump_task->mm) { + if (p->flags & PF_KTHREAD) + continue; + t = kzalloc(offsetof(struct elf_thread_core_info, notes[info->thread_notes]), GFP_ATOMIC); @@ -1726,6 +1729,9 @@ static int fill_note_info(struct elfhdr rcu_read_lock(); do_each_thread(g, p) if (current->mm == p->mm && current != p) { + if (p->flags & PF_KTHREAD) + continue; + ets = kzalloc(sizeof(*ets), GFP_ATOMIC); if (!ets) { rcu_read_unlock(); --- 26-rc2/fs/binfmt_elf_fdpic.c~CD_SKIP_KTHREAD 2008-06-02 20:46:54.000000000 +0400 +++ 26-rc2/fs/binfmt_elf_fdpic.c 2008-06-16 18:57:46.000000000 +0400 @@ -1626,6 +1626,9 @@ static int elf_fdpic_core_dump(long sign rcu_read_lock(); do_each_thread(g,p) if (current->mm == p->mm && current != p) { + if (p->flags & PF_KTHREAD) + continue; + tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC); if (!tmp) { rcu_read_unlock();
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