From: Linus Torvalds Date: Tue, 2 Feb 2010 20:37:44 +0000 (-0800) Subject: Fix 'flush_old_exec()/setup_new_exec()' split X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7ab02af428c2d312c0cf8fb0b01cc1eb21131a3d;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git Fix 'flush_old_exec()/setup_new_exec()' split Commit 221af7f87b9 ("Split 'flush_old_exec' into two functions") split the function at the point of no return - ie right where there were no more error cases to check. That made sense from a technical standpoint, but when we then also combined it with the actual personality setting going in between flush_old_exec() and setup_new_exec(), it needs to be a bit more careful. In particular, we need to make sure that we really flush the old personality bits in the 'flush' stage, rather than later in the 'setup' stage, since otherwise we might be flushing the _new_ personality state that we're just setting up. So this moves the flags and personality flushing (and 'flush_thread()', which is the arch-specific function that generally resets lazy FP state etc) of the old process into flush_old_exec(), so that it doesn't affect any state that execve() is setting up for the new process environment. This was reported by Michal Simek as breaking his Microblaze qemu environment. Reported-and-tested-by: Michal Simek Cc: Peter Anvin Signed-off-by: Linus Torvalds --- diff --git a/fs/exec.c b/fs/exec.c index 675c3f44c2ea..0790a107ff7e 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -961,6 +961,11 @@ int flush_old_exec(struct linux_binprm * bprm) goto out; bprm->mm = NULL; /* We're using it now */ + + current->flags &= ~PF_RANDOMIZE; + flush_thread(); + current->personality &= ~bprm->per_clear; + return 0; out: @@ -997,9 +1002,6 @@ void setup_new_exec(struct linux_binprm * bprm) tcomm[i] = '\0'; set_task_comm(current, tcomm); - current->flags &= ~PF_RANDOMIZE; - flush_thread(); - /* Set the new mm task size. We have to do that late because it may * depend on TIF_32BIT which is only updated in flush_thread() on * some architectures like powerpc @@ -1015,8 +1017,6 @@ void setup_new_exec(struct linux_binprm * bprm) set_dumpable(current->mm, suid_dumpable); } - current->personality &= ~bprm->per_clear; - /* * Flush performance counters when crossing a * security domain: