KASAN: use-after-free Read in iwcm_deref_id

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: f8788d86 Linux 5.6-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164503d9e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=5d2e033af114153f
dashboard link: https://syzkaller.appspot.com/bug?extid=cb0c054eabfba4342146
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

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+cb0c05...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in dealloc_work_entries drivers/infiniband/core/iwcm.c:162 [inline]
BUG: KASAN: use-after-free in free_cm_id drivers/infiniband/core/iwcm.c:202 [inline]
BUG: KASAN: use-after-free in iwcm_deref_id+0xf6/0x170 drivers/infiniband/core/iwcm.c:215
Read of size 8 at addr ffff8880a0d05978 by task syz-executor.2/15428

CPU: 1 PID: 15428 Comm: syz-executor.2 Not tainted 5.6.0-rc3-syzkaller #0
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+0x1fb/0x318 lib/dump_stack.c:118
print_address_description+0x74/0x5c0 mm/kasan/report.c:374
__kasan_report+0x149/0x1c0 mm/kasan/report.c:506
kasan_report+0x26/0x50 mm/kasan/common.c:641
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
dealloc_work_entries drivers/infiniband/core/iwcm.c:162 [inline]
free_cm_id drivers/infiniband/core/iwcm.c:202 [inline]
iwcm_deref_id+0xf6/0x170 drivers/infiniband/core/iwcm.c:215
destroy_cm_id+0x4b2/0x5b0 drivers/infiniband/core/iwcm.c:442
iw_destroy_cm_id+0x15/0x20 drivers/infiniband/core/iwcm.c:453
cma_iw_listen drivers/infiniband/core/cma.c:2453 [inline]
rdma_listen+0x6dc/0x9a0 drivers/infiniband/core/cma.c:3614
cma_listen_on_dev+0x678/0x8e0 drivers/infiniband/core/cma.c:2501
cma_listen_on_all drivers/infiniband/core/cma.c:2514 [inline]
rdma_listen+0x43b/0x9a0 drivers/infiniband/core/cma.c:3622
ucma_listen+0x245/0x300 drivers/infiniband/core/ucma.c:1092
ucma_write+0x2da/0x360 drivers/infiniband/core/ucma.c:1684
__vfs_write+0xb8/0x740 fs/read_write.c:494
vfs_write+0x270/0x580 fs/read_write.c:558
ksys_write+0x117/0x220 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write fs/read_write.c:620 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:620
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c449
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe499194c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe4991956d4 RCX: 000000000045c449
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008
R13: 0000000000000cbe R14: 00000000004cea14 R15: 0000000000000007

Allocated by task 15428:
save_stack mm/kasan/common.c:72 [inline]
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
kmem_cache_alloc_trace+0x221/0x2f0 mm/slab.c:3551
kmalloc include/linux/slab.h:555 [inline]
alloc_work_entries drivers/infiniband/core/iwcm.c:172 [inline]
iw_cm_listen+0xdd/0x4a0 drivers/infiniband/core/iwcm.c:571
cma_iw_listen drivers/infiniband/core/cma.c:2450 [inline]
rdma_listen+0x698/0x9a0 drivers/infiniband/core/cma.c:3614
cma_listen_on_dev+0x678/0x8e0 drivers/infiniband/core/cma.c:2501
cma_listen_on_all drivers/infiniband/core/cma.c:2514 [inline]
rdma_listen+0x43b/0x9a0 drivers/infiniband/core/cma.c:3622
ucma_listen+0x245/0x300 drivers/infiniband/core/ucma.c:1092
ucma_write+0x2da/0x360 drivers/infiniband/core/ucma.c:1684
__vfs_write+0xb8/0x740 fs/read_write.c:494
vfs_write+0x270/0x580 fs/read_write.c:558
ksys_write+0x117/0x220 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write fs/read_write.c:620 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:620
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 15428:
save_stack mm/kasan/common.c:72 [inline]
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:337 [inline]
__kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476
kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
__cache_free mm/slab.c:3426 [inline]
kfree+0x10d/0x220 mm/slab.c:3757
dealloc_work_entries drivers/infiniband/core/iwcm.c:163 [inline]
alloc_work_entries drivers/infiniband/core/iwcm.c:174 [inline]
iw_cm_listen+0x288/0x4a0 drivers/infiniband/core/iwcm.c:571
cma_iw_listen drivers/infiniband/core/cma.c:2450 [inline]
rdma_listen+0x698/0x9a0 drivers/infiniband/core/cma.c:3614
cma_listen_on_dev+0x678/0x8e0 drivers/infiniband/core/cma.c:2501
cma_listen_on_all drivers/infiniband/core/cma.c:2514 [inline]
rdma_listen+0x43b/0x9a0 drivers/infiniband/core/cma.c:3622
ucma_listen+0x245/0x300 drivers/infiniband/core/ucma.c:1092
ucma_write+0x2da/0x360 drivers/infiniband/core/ucma.c:1684
__vfs_write+0xb8/0x740 fs/read_write.c:494
vfs_write+0x270/0x580 fs/read_write.c:558
ksys_write+0x117/0x220 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write fs/read_write.c:620 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:620
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a0d05800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 376 bytes inside of
512-byte region [ffff8880a0d05800, ffff8880a0d05a00)
The buggy address belongs to the page:
page:ffffea0002834140 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0001019988 ffffea000280e088 ffff8880aa400a80
raw: 0000000000000000 ffff8880a0d05000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a0d05800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a0d05880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a0d05900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880a0d05980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a0d05a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[Jason Gunthorpe]

On Tue, Feb 25, 2020 at 11:00:13PM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: f8788d86 Linux 5.6-rc3
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=164503d9e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=5d2e033af114153f
> dashboard link: https://syzkaller.appspot.com/bug?extid=cb0c054eabfba4342146
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
>
> 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+cb0c05...@syzkaller.appspotmail.com

#syz dup KASAN: use-after-free Read in rdma_listen (2)