From: Oleg Nesterov Date: Tue, 31 Jan 2012 16:15:11 +0000 (+0100) Subject: proc: make sure mem_open() doesn't pin the target's memory X-Git-Tag: v3.3-rc3~41 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d08f2c7139790c268820a2e590795cb8333181a;p=pandora-kernel.git proc: make sure mem_open() doesn't pin the target's memory Once /proc/pid/mem is opened, the memory can't be released until mem_release() even if its owner exits. Change mem_open() to do atomic_inc(mm_count) + mmput(), this only pins mm_struct. Change mem_rw() to do atomic_inc_not_zero(mm_count) before access_remote_vm(), this verifies that this mm is still alive. I am not sure what should mem_rw() return if atomic_inc_not_zero() fails. With this patch it returns zero to match the "mm == NULL" case, may be it should return -EINVAL like it did before e268337d. Perhaps it makes sense to add the additional fatal_signal_pending() check into the main loop, to ensure we do not hold this memory if the target task was oom-killed. Cc: stable@kernel.org Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed