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authorPeter Zijlstra <peterz@infradead.org>2022-08-22 13:18:18 +0200
committerPeter Zijlstra <peterz@infradead.org>2022-09-07 21:53:48 +0200
commit1fbcaa923ce2d7e6de17abd74fa076dc1e0be1a2 (patch)
treef6b83d9a4edbd1c8cdc2ba1b48635fa2096a2eb6
parent5950e5d574c636a07dd21a872c2f8b41f6d20c55 (diff)
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freezer,umh: Clean up freezer/initrd interaction
handle_initrd() marks itself as PF_FREEZER_SKIP in order to ensure that the UMH, which is going to freeze the system, doesn't indefinitely wait for it's caller. Rework things by adding UMH_FREEZABLE to indicate the completion is freezable. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20220822114648.791019324@infradead.org
-rw-r--r--include/linux/umh.h9
-rw-r--r--init/do_mounts_initrd.c10
-rw-r--r--kernel/umh.c8
3 files changed, 14 insertions, 13 deletions
diff --git a/include/linux/umh.h b/include/linux/umh.h
index 244aff638220..5d1f6129b847 100644
--- a/include/linux/umh.h
+++ b/include/linux/umh.h
@@ -11,10 +11,11 @@
struct cred;
struct file;
-#define UMH_NO_WAIT 0 /* don't wait at all */
-#define UMH_WAIT_EXEC 1 /* wait for the exec, but not the process */
-#define UMH_WAIT_PROC 2 /* wait for the process to complete */
-#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */
+#define UMH_NO_WAIT 0x00 /* don't wait at all */
+#define UMH_WAIT_EXEC 0x01 /* wait for the exec, but not the process */
+#define UMH_WAIT_PROC 0x02 /* wait for the process to complete */
+#define UMH_KILLABLE 0x04 /* wait for EXEC/PROC killable */
+#define UMH_FREEZABLE 0x08 /* wait for EXEC/PROC freezable */
struct subprocess_info {
struct work_struct work;
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 327962ea354c..34731241377d 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -99,19 +99,11 @@ static void __init handle_initrd(void)
init_mkdir("/old", 0700);
init_chdir("/old");
- /*
- * In case that a resume from disk is carried out by linuxrc or one of
- * its children, we need to tell the freezer not to wait for us.
- */
- current->flags |= PF_FREEZER_SKIP;
-
info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
GFP_KERNEL, init_linuxrc, NULL, NULL);
if (!info)
return;
- call_usermodehelper_exec(info, UMH_WAIT_PROC);
-
- current->flags &= ~PF_FREEZER_SKIP;
+ call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);
/* move initrd to rootfs' /old */
init_mount("..", ".", NULL, MS_MOVE, NULL);
diff --git a/kernel/umh.c b/kernel/umh.c
index b989736e8707..8945eaf4c671 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -28,6 +28,7 @@
#include <linux/async.h>
#include <linux/uaccess.h>
#include <linux/initrd.h>
+#include <linux/freezer.h>
#include <trace/events/module.h>
@@ -436,6 +437,9 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
if (wait == UMH_NO_WAIT) /* task has freed sub_info */
goto unlock;
+ if (wait & UMH_FREEZABLE)
+ freezer_do_not_count();
+
if (wait & UMH_KILLABLE) {
retval = wait_for_completion_killable(&done);
if (!retval)
@@ -448,6 +452,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
}
wait_for_completion(&done);
+
+ if (wait & UMH_FREEZABLE)
+ freezer_count();
+
wait_done:
retval = sub_info->retval;
out: