By discussion with Mandeep Singh Baines <[email protected]>. Change dump_write(), dump_seek() and do_coredump() to check signal_pending() and abort if it is true.
We add the new trivial helper, dump_interrupted(), to document that this probably needs more work and to simplify the potential freezer changes. Perhaps it will have more callers. Ideally it should do try_to_freeze() but then we need the unpleasant changes in dump_write() and wait_for_dump_helpers(). So far we simply accept the fact that the freezer can truncate a core-dump but at least you can reliably suspend. Signed-off-by: Oleg Nesterov <[email protected]> --- fs/coredump.c | 20 +++++++++++++++++--- 1 files changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index 5503d94..66f65f0 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -418,6 +418,17 @@ static void coredump_finish(struct mm_struct *mm, bool core_dumped) mm->core_state = NULL; } +static bool dump_interrupted(void) +{ + /* + * SIGKILL or freezing() interrupt the coredumping. Perhaps we + * can do try_to_freeze() and check __fatal_signal_pending(), + * but then we need to teach dump_write() to restart and clear + * TIF_SIGPENDING. + */ + return signal_pending(current); +} + static void wait_for_dump_helpers(struct file *file) { struct pipe_inode_info *pipe; @@ -636,7 +647,7 @@ void do_coredump(siginfo_t *siginfo) if (displaced) put_files_struct(displaced); - core_dumped = binfmt->core_dump(&cprm); + core_dumped = !dump_interrupted() && binfmt->core_dump(&cprm); if (ispipe && core_pipe_limit) wait_for_dump_helpers(cprm.file); @@ -664,7 +675,9 @@ fail: */ int dump_write(struct file *file, const void *addr, int nr) { - return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; + return !dump_interrupted() && + access_ok(VERIFY_READ, addr, nr) && + file->f_op->write(file, addr, nr, &file->f_pos) == nr; } EXPORT_SYMBOL(dump_write); @@ -673,7 +686,8 @@ int dump_seek(struct file *file, loff_t off) int ret = 1; if (file->f_op->llseek && file->f_op->llseek != no_llseek) { - if (file->f_op->llseek(file, off, SEEK_CUR) < 0) + if (dump_interrupted() || + file->f_op->llseek(file, off, SEEK_CUR) < 0) return 0; } else { char *buf = (char *)get_zeroed_page(GFP_KERNEL); -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
