On Wed, Jan 02, 2019 at 10:44:50PM +0100, Rafael J. Wysocki wrote: > On Wed, Jan 2, 2019 at 8:53 PM Linus Torvalds > <[email protected]> wrote: > > [cut] > > > Greg, Rafael: it does strike me that the "BUG_ON()" in > > sysfs_create_file_ns() could easily have been a > > > > if (WARN_ON(..)) > > return -EINVAL; > > > > which would have made the machine boot and probably make things easier > > for normal users to report. The kernel test robot doesn't care, but > > non-booting kernels are usually not nice to debug or report for normal > > human beings.. > > I agree. > > This isn't a good enough reason to crash the kernel IMO.
I agree too. Here's a patch for this, I'll queue it up after -rc1 is out. Rafael, look good to you? -------------- From: Greg Kroah-Hartman <[email protected]> Subject: [PATCH] sysfs: convert BUG_ON to WARN_ON It's rude to crash the system just because the developer did something wrong, as it prevents them from usually even seeing what went wrong. So convert the few BUG_ON() calls that have snuck into the sysfs code over the years to WARN_ON() to make it more "friendly". All of these are able to be recovered from, so it makes no sense to crash. Reported-by: Linus Torvalds <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/sysfs/dir.c | 3 ++- fs/sysfs/file.c | 6 ++++-- fs/sysfs/group.c | 3 ++- fs/sysfs/symlink.c | 3 ++- 4 files changed, 10 insertions(+), 5 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index feeae8081c22..aa85f2874a9f 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -43,7 +43,8 @@ int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) kuid_t uid; kgid_t gid; - BUG_ON(!kobj); + if (WARN_ON(!kobj)) + return -EINVAL; if (kobj->parent) parent = kobj->parent->sd; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index bb71db63c99c..51398457fe00 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -325,7 +325,8 @@ int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, kuid_t uid; kgid_t gid; - BUG_ON(!kobj || !kobj->sd || !attr); + if (WARN_ON(!kobj || !kobj->sd || !attr)) + return -EINVAL; kobject_get_ownership(kobj, &uid, &gid); return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, @@ -537,7 +538,8 @@ int sysfs_create_bin_file(struct kobject *kobj, kuid_t uid; kgid_t gid; - BUG_ON(!kobj || !kobj->sd || !attr); + if (WARN_ON(!kobj || !kobj->sd || !attr)) + return -EINVAL; kobject_get_ownership(kobj, &uid, &gid); return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true, diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 1eb2d6307663..57038604d4a8 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -112,7 +112,8 @@ static int internal_create_group(struct kobject *kobj, int update, kgid_t gid; int error; - BUG_ON(!kobj || (!update && !kobj->sd)); + if (WARN_ON(!kobj || (!update && !kobj->sd))) + return -EINVAL; /* Updates may happen before the object has been instantiated */ if (unlikely(update && !kobj->sd)) diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index 215c225b2ca1..c4deecc80f67 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -23,7 +23,8 @@ static int sysfs_do_create_link_sd(struct kernfs_node *parent, { struct kernfs_node *kn, *target = NULL; - BUG_ON(!name || !parent); + if (WARN_ON(!name || !parent)) + return -EINVAL; /* * We don't own @target_kobj and it may be removed at any time. -- 2.20.1
