From 24d5288f06ed8b3a368eba967d587cdb012dfdf7 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 25 Jul 2008 01:47:40 -0700 Subject: [PATCH] coredump: elf_core_dump: skip kernel threads 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 Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 6 ++++++ fs/binfmt_elf_fdpic.c | 3 +++ 2 files changed, 9 insertions(+) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 639d2d8b571..bad7d8770d7 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1520,6 +1520,9 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, 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); @@ -1724,6 +1727,9 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, 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(); diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index d051a32e627..71bcc4b4d08 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1626,6 +1626,9 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs, 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(); -- 2.41.1