From 009bb421b6ceb7916ce627023d0eb7ced04c8910 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Sun, 3 Mar 2019 14:00:46 -0800 Subject: workqueue, lockdep: Fix an alloc_workqueue() error path This patch fixes a use-after-free and a memory leak in an alloc_workqueue() error path. Repoted by syzkaller and KASAN: BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:197 [inline] BUG: KASAN: use-after-free in lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1023 Read of size 8 at addr ffff888090fc2698 by task syz-executor134/7858 CPU: 1 PID: 7858 Comm: syz-executor134 Not tainted 5.0.0-rc8-next-20190301 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __read_once_size include/linux/compiler.h:197 [inline] lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1023 wq_init_lockdep kernel/workqueue.c:3444 [inline] alloc_workqueue+0x427/0xe70 kernel/workqueue.c:4263 ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 misc_open+0x398/0x4c0 drivers/char/misc.c:141 chrdev_open+0x247/0x6b0 fs/char_dev.c:417 do_dentry_open+0x488/0x1160 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3416 [inline] path_openat+0x10e9/0x46e0 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Allocated by task 7789: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511 __do_kmalloc mm/slab.c:3726 [inline] __kmalloc+0x15c/0x740 mm/slab.c:3735 kmalloc include/linux/slab.h:553 [inline] kzalloc include/linux/slab.h:743 [inline] alloc_workqueue+0x13c/0xe70 kernel/workqueue.c:4236 ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 misc_open+0x398/0x4c0 drivers/char/misc.c:141 chrdev_open+0x247/0x6b0 fs/char_dev.c:417 do_dentry_open+0x488/0x1160 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3416 [inline] path_openat+0x10e9/0x46e0 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7789: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3821 alloc_workqueue+0xc3e/0xe70 kernel/workqueue.c:4295 ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 misc_open+0x398/0x4c0 drivers/char/misc.c:141 chrdev_open+0x247/0x6b0 fs/char_dev.c:417 do_dentry_open+0x488/0x1160 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3416 [inline] path_openat+0x10e9/0x46e0 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888090fc2580 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 280 bytes inside of 512-byte region [ffff888090fc2580, ffff888090fc2780) Reported-by: syzbot+17335689e239ce135d8b@syzkaller.appspotmail.com Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Will Deacon Fixes: 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") Link: https://lkml.kernel.org/r/20190303220046.29448-1-bvanassche@acm.org Signed-off-by: Ingo Molnar --- kernel/workqueue.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e163e7a7f5e5..ecdd5e6f2166 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4194,6 +4194,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt, return wq; err_free_wq: + wq_unregister_lockdep(wq); + wq_free_lockdep(wq); free_workqueue_attrs(wq->unbound_attrs); kfree(wq); return NULL; -- cgit v1.2.3-55-g7522