KASAN: use-after-free Read in addr_handler

From: syzbot
Date: Thu Dec 13 2018 - 10:27:07 EST

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Hello,

syzbot found the following crash on:

HEAD commit: f5d582777bcb Merge branch 'for-linus' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14e556fb400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c8970c89a0efbb23
dashboard link: https://syzkaller.appspot.com/bug?extid=b358909d8d01556b790b
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b358909d8d01556b790b@xxxxxxxxxxxxxxxxxxxxxxxxx

IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218
Read of size 8 at addr ffff88818e1b5050 by task kworker/u4:3/394

CPU: 1 PID: 394 Comm: kworker/u4:3 Not tainted 4.20.0-rc6+ #274
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ib_addr process_one_req
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
__lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218
lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
__mutex_lock_common kernel/locking/mutex.c:925 [inline]
__mutex_lock+0x166/0x16f0 kernel/locking/mutex.c:1072
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
addr_handler+0xed/0x420 drivers/infiniband/core/cma.c:2967
process_one_req+0x1a9/0x920 drivers/infiniband/core/addr.c:643
process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 25482:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
kmalloc include/linux/slab.h:546 [inline]
kzalloc include/linux/slab.h:741 [inline]
__rdma_create_id+0xdf/0x650 drivers/infiniband/core/cma.c:876
ucma_create_id+0x39b/0x990 drivers/infiniband/core/ucma.c:506
ucma_write+0x365/0x460 drivers/infiniband/core/ucma.c:1689
__vfs_write+0x119/0x9f0 fs/read_write.c:485
vfs_write+0x1fc/0x560 fs/read_write.c:549
ksys_write+0x101/0x260 fs/read_write.c:598
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__ia32_sys_write+0x71/0xb0 fs/read_write.c:607
do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 25482:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3817
rdma_destroy_id+0x835/0xcc0 drivers/infiniband/core/cma.c:1846
ucma_destroy_id+0x3ae/0x550 drivers/infiniband/core/ucma.c:638
ucma_write+0x365/0x460 drivers/infiniband/core/ucma.c:1689
__vfs_write+0x119/0x9f0 fs/read_write.c:485
vfs_write+0x1fc/0x560 fs/read_write.c:549
ksys_write+0x101/0x260 fs/read_write.c:598
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__ia32_sys_write+0x71/0xb0 fs/read_write.c:607
do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff88818e1b4cc0
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 912 bytes inside of
2048-byte region [ffff88818e1b4cc0, ffff88818e1b54c0)
The buggy address belongs to the page:
page:ffffea0006386d00 count:1 mapcount:0 mapping:ffff8881da800c40 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea00075df808 ffffea0006ffd708 ffff8881da800c40
raw: 0000000000000000 ffff88818e1b4440 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88818e1b4f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88818e1b4f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff88818e1b5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^
ffff88818e1b5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88818e1b5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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Next message: Michael S. Tsirkin: "Re: [PATCH net-next 0/3] vhost: accelerate metadata access through vmap()"
Previous message: Paul E. McKenney: "Re: [PATCH] srcu: Remove srcu_queue_delayed_work_on()"
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