From 5631f2c18f4b2845b3e97df1c659c5094a17605f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bruno=20Pr=C3=A9mont?= Date: Tue, 3 Apr 2012 09:59:48 +0200 Subject: [PATCH] sysfs: Prevent crash on unset sysfs group attributes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Do not let the kernel crash when a device is registered with sysfs while group attributes are not set (aka NULL). Warn about the offender with some information about the offending device. This would warn instead of trying NULL pointer deref like: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] internal_create_group+0x83/0x1a0 PGD 0 Oops: 0000 [#1] SMP CPU 0 Modules linked in: Pid: 1, comm: swapper/0 Not tainted 3.4.0-rc1-x86_64 #3 HP ProLiant DL360 G4 RIP: 0010:[] [] internal_create_group+0x83/0x1a0 RSP: 0018:ffff88019485fd70 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001 RDX: ffff880192e99908 RSI: ffff880192e99630 RDI: ffffffff81a26c60 RBP: ffff88019485fdc0 R08: 0000000000000000 R09: 0000000000000000 R10: ffff880192e99908 R11: 0000000000000000 R12: ffffffff81a16a00 R13: ffff880192e99908 R14: ffffffff81a16900 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88019bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000001a0c000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper/0 (pid: 1, threadinfo ffff88019485e000, task ffff880194878000) Stack: ffff88019485fdd0 ffff880192da9d60 0000000000000000 ffff880192e99908 ffff880192e995d8 0000000000000001 ffffffff81a16a00 ffff880192da9d60 0000000000000000 0000000000000000 ffff88019485fdd0 ffffffff811527be Call Trace: [] sysfs_create_group+0xe/0x10 [] device_add_groups+0x46/0x80 [] device_add+0x46d/0x6a0 ... Signed-off-by: Bruno Prémont Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/group.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index dd1701caecc9..2df555c66d57 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -67,7 +67,11 @@ static int internal_create_group(struct kobject *kobj, int update, /* Updates may happen before the object has been instantiated */ if (unlikely(update && !kobj->sd)) return -EINVAL; - + if (!grp->attrs) { + WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n", + kobj->name, grp->name ? "" : grp->name); + return -EINVAL; + } if (grp->name) { error = sysfs_create_subdir(kobj, grp->name, &sd); if (error) -- 2.39.5