drivers/infiniband/core/device.c | 2 ++ 1 file changed, 2 insertions(+)
Syzbot reported a slab-use-after-free with the following call trace:
==================================================================
BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099
Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025
CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
Hardware name: Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0x16e/0x5b0 mm/kasan/report.c:521
kasan_report+0x143/0x180 mm/kasan/report.c:634
kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
__asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
nla_put+0xd3/0x150 lib/nlattr.c:1099
nla_put_string include/net/netlink.h:1621 [inline]
fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265
rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857
ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344
ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460
rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:709 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:724
____sys_sendmsg+0x53a/0x860 net/socket.c:2564
___sys_sendmsg net/socket.c:2618 [inline]
__sys_sendmsg+0x269/0x350 net/socket.c:2650
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f42d1b8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ...
RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169
RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c
RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8
</TASK>
Allocated by task 10025:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4294 [inline]
__kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313
__kmemdup_nul mm/util.c:61 [inline]
kstrdup+0x42/0x100 mm/util.c:81
kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274
dev_set_name+0xd5/0x120 drivers/base/core.c:3468
assign_name drivers/infiniband/core/device.c:1202 [inline]
ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384
rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:709 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:724
____sys_sendmsg+0x53a/0x860 net/socket.c:2564
___sys_sendmsg net/socket.c:2618 [inline]
__sys_sendmsg+0x269/0x350 net/socket.c:2650
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 10035:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2353 [inline]
slab_free mm/slub.c:4609 [inline]
kfree+0x196/0x430 mm/slub.c:4757
kobject_rename+0x38f/0x410 lib/kobject.c:524
device_rename+0x16a/0x200 drivers/base/core.c:4525
ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402
nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:709 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:724
____sys_sendmsg+0x53a/0x860 net/socket.c:2564
___sys_sendmsg net/socket.c:2618 [inline]
__sys_sendmsg+0x269/0x350 net/socket.c:2650
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
This is because if rename device happens, the old name is freed in
ib_device_rename() with lock, but fill_nldev_handle() may visit the dev
name locklessly triggered by rxe_newlink().
Fix this by add lock around rdma_nl_notify_event() in
ib_device_notify_register().
Reported-by: syzbot+f60349ba1f9f08df349f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8
Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring")
Signed-off-by: Wang Liang <wangliang74@huawei.com>
---
drivers/infiniband/core/device.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 0ded91f056f3..4536621ada0d 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device)
u32 port;
int ret;
+ down_write(&devices_rwsem);
ret = rdma_nl_notify_event(device, 0, RDMA_REGISTER_EVENT);
+ up_write(&devices_rwsem);
if (ret)
return;
--
2.34.1On Mon, Mar 10, 2025 at 02:45:16PM +0800, Wang Liang wrote:
> Syzbot reported a slab-use-after-free with the following call trace:
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099
> Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025
>
> CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
> Hardware name: Google Compute Engine, BIOS Google 02/12/2025
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:408 [inline]
> print_report+0x16e/0x5b0 mm/kasan/report.c:521
> kasan_report+0x143/0x180 mm/kasan/report.c:634
> kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
> __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
> nla_put+0xd3/0x150 lib/nlattr.c:1099
> nla_put_string include/net/netlink.h:1621 [inline]
> fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265
> rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857
> ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344
> ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460
> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:709 [inline]
> __sock_sendmsg+0x221/0x270 net/socket.c:724
> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> ___sys_sendmsg net/socket.c:2618 [inline]
> __sys_sendmsg+0x269/0x350 net/socket.c:2650
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f42d1b8d169
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ...
> RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169
> RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c
> RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8
> </TASK>
>
> Allocated by task 10025:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
> __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
> kasan_kmalloc include/linux/kasan.h:260 [inline]
> __do_kmalloc_node mm/slub.c:4294 [inline]
> __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313
> __kmemdup_nul mm/util.c:61 [inline]
> kstrdup+0x42/0x100 mm/util.c:81
> kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274
> dev_set_name+0xd5/0x120 drivers/base/core.c:3468
> assign_name drivers/infiniband/core/device.c:1202 [inline]
> ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384
> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:709 [inline]
> __sock_sendmsg+0x221/0x270 net/socket.c:724
> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> ___sys_sendmsg net/socket.c:2618 [inline]
> __sys_sendmsg+0x269/0x350 net/socket.c:2650
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Freed by task 10035:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2353 [inline]
> slab_free mm/slub.c:4609 [inline]
> kfree+0x196/0x430 mm/slub.c:4757
> kobject_rename+0x38f/0x410 lib/kobject.c:524
> device_rename+0x16a/0x200 drivers/base/core.c:4525
> ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402
> nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146
> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:709 [inline]
> __sock_sendmsg+0x221/0x270 net/socket.c:724
> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> ___sys_sendmsg net/socket.c:2618 [inline]
> __sys_sendmsg+0x269/0x350 net/socket.c:2650
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> This is because if rename device happens, the old name is freed in
> ib_device_rename() with lock, but fill_nldev_handle() may visit the dev
> name locklessly triggered by rxe_newlink().
>
> Fix this by add lock around rdma_nl_notify_event() in
> ib_device_notify_register().
>
> Reported-by: syzbot+f60349ba1f9f08df349f@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8
> Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring")
> Signed-off-by: Wang Liang <wangliang74@huawei.com>
> ---
> drivers/infiniband/core/device.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index 0ded91f056f3..4536621ada0d 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device)
> u32 port;
> int ret;
>
> + down_write(&devices_rwsem);
The analysis looks correct to me, however this should be down_read(&devices_rwsem)
together with comment about possible race with RDMA netlink, which can change
internals of struct ib_device.
I wonder if this read semaphore should be hold for whole
ib_device_notify_register() function and not only for RDMA_REGISTER_EVENT event.
Thanks
> ret = rdma_nl_notify_event(device, 0, RDMA_REGISTER_EVENT);
> + up_write(&devices_rwsem);
> if (ret)
> return;
>
> --
> 2.34.1
>
>
在 2025/3/10 18:14, Leon Romanovsky 写道:
> On Mon, Mar 10, 2025 at 02:45:16PM +0800, Wang Liang wrote:
>> Syzbot reported a slab-use-after-free with the following call trace:
>>
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099
>> Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025
>>
>> CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
>> Hardware name: Google Compute Engine, BIOS Google 02/12/2025
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:94 [inline]
>> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>> print_address_description mm/kasan/report.c:408 [inline]
>> print_report+0x16e/0x5b0 mm/kasan/report.c:521
>> kasan_report+0x143/0x180 mm/kasan/report.c:634
>> kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
>> __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
>> nla_put+0xd3/0x150 lib/nlattr.c:1099
>> nla_put_string include/net/netlink.h:1621 [inline]
>> fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265
>> rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857
>> ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344
>> ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460
>> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
>> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
>> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
>> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>> sock_sendmsg_nosec net/socket.c:709 [inline]
>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>> ___sys_sendmsg net/socket.c:2618 [inline]
>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7f42d1b8d169
>> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ...
>> RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169
>> RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c
>> RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
>> R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8
>> </TASK>
>>
>> Allocated by task 10025:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
>> __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
>> kasan_kmalloc include/linux/kasan.h:260 [inline]
>> __do_kmalloc_node mm/slub.c:4294 [inline]
>> __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313
>> __kmemdup_nul mm/util.c:61 [inline]
>> kstrdup+0x42/0x100 mm/util.c:81
>> kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274
>> dev_set_name+0xd5/0x120 drivers/base/core.c:3468
>> assign_name drivers/infiniband/core/device.c:1202 [inline]
>> ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384
>> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
>> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
>> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
>> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>> sock_sendmsg_nosec net/socket.c:709 [inline]
>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>> ___sys_sendmsg net/socket.c:2618 [inline]
>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> Freed by task 10035:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
>> poison_slab_object mm/kasan/common.c:247 [inline]
>> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
>> kasan_slab_free include/linux/kasan.h:233 [inline]
>> slab_free_hook mm/slub.c:2353 [inline]
>> slab_free mm/slub.c:4609 [inline]
>> kfree+0x196/0x430 mm/slub.c:4757
>> kobject_rename+0x38f/0x410 lib/kobject.c:524
>> device_rename+0x16a/0x200 drivers/base/core.c:4525
>> ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402
>> nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146
>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>> sock_sendmsg_nosec net/socket.c:709 [inline]
>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>> ___sys_sendmsg net/socket.c:2618 [inline]
>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> This is because if rename device happens, the old name is freed in
>> ib_device_rename() with lock, but fill_nldev_handle() may visit the dev
>> name locklessly triggered by rxe_newlink().
>>
>> Fix this by add lock around rdma_nl_notify_event() in
>> ib_device_notify_register().
>>
>> Reported-by: syzbot+f60349ba1f9f08df349f@syzkaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8
>> Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring")
>> Signed-off-by: Wang Liang <wangliang74@huawei.com>
>> ---
>> drivers/infiniband/core/device.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
>> index 0ded91f056f3..4536621ada0d 100644
>> --- a/drivers/infiniband/core/device.c
>> +++ b/drivers/infiniband/core/device.c
>> @@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device)
>> u32 port;
>> int ret;
>>
>> + down_write(&devices_rwsem);
> The analysis looks correct to me, however this should be down_read(&devices_rwsem)
> together with comment about possible race with RDMA netlink, which can change
> internals of struct ib_device.
>
> I wonder if this read semaphore should be hold for whole
> ib_device_notify_register() function and not only for RDMA_REGISTER_EVENT event.
>
> Thanks
Yes, you are right! The RDMA_NETDEV_ATTACH_EVENT event in function
ib_device_notify_register() can also visit the dev name locklessly:
rxe_newlink
...
ib_device_notify_register
rdma_nl_notify_event(RDMA_NETDEV_ATTACH_EVENT)
fill_mon_netdev_association
// visit dev_name without devices_rwsem
What's more, the following trace may also trigger the issue when function
nldev_set_doit() rename device:
(1)
RDMA_NLDEV_CMD_GET
nldev_get_doit
fill_dev_info
fill_nldev_handle
// visit dev_name without devices_rwsem
(2)
RDMA_NLDEV_CMD_PORT_GET
nldev_port_get_doit
fill_port_info
fill_nldev_handle
// visit dev_name without devices_rwsem
(3)
RDMA_NLDEV_CMD_RES_GET
nldev_res_get_doit
fill_res_info
fill_nldev_handle
// visit dev_name without devices_rwsem
And more...
However, some scenarios hold devices_rwsem, like function
nldev_get_dumpit(),
which was modified by 921eab1143aa("RDMA/devices: Re-organize device.c
locking"):
RDMA_NLDEV_CMD_GET
nldev_get_dumpit
ib_enum_all_devs
down_read(&devices_rwsem); // hold devices_rwsem read
_nldev_get_dumpit
fill_dev_info
fill_nldev_handle
// visit dev_name with devices_rwsem
up_read(&devices_rwsem);
So only hold devices_rwsem for whole ib_device_notify_register() may be
not enough.
How about add down_read(&devices_rwsem) around
fill_dev_info()/fill_port_info()/
fill_res_info()/ib_device_notify_register().
Looking forward to more replies. Thanks.
>> ret = rdma_nl_notify_event(device, 0, RDMA_REGISTER_EVENT);
>> + up_write(&devices_rwsem);
>> if (ret)
>> return;
>>
>> --
>> 2.34.1
>>
>>
On Tue, Mar 11, 2025 at 10:55:42AM +0800, Wang Liang wrote:
>
> 在 2025/3/10 18:14, Leon Romanovsky 写道:
> > On Mon, Mar 10, 2025 at 02:45:16PM +0800, Wang Liang wrote:
> > > Syzbot reported a slab-use-after-free with the following call trace:
> > >
> > > ==================================================================
> > > BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099
> > > Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025
> > >
> > > CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
> > > Hardware name: Google Compute Engine, BIOS Google 02/12/2025
> > > Call Trace:
> > > <TASK>
> > > __dump_stack lib/dump_stack.c:94 [inline]
> > > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> > > print_address_description mm/kasan/report.c:408 [inline]
> > > print_report+0x16e/0x5b0 mm/kasan/report.c:521
> > > kasan_report+0x143/0x180 mm/kasan/report.c:634
> > > kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
> > > __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
> > > nla_put+0xd3/0x150 lib/nlattr.c:1099
> > > nla_put_string include/net/netlink.h:1621 [inline]
> > > fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265
> > > rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857
> > > ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344
> > > ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460
> > > rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
> > > rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
> > > rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
> > > nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
> > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> > > sock_sendmsg_nosec net/socket.c:709 [inline]
> > > __sock_sendmsg+0x221/0x270 net/socket.c:724
> > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> > > ___sys_sendmsg net/socket.c:2618 [inline]
> > > __sys_sendmsg+0x269/0x350 net/socket.c:2650
> > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> > > entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > > RIP: 0033:0x7f42d1b8d169
> > > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ...
> > > RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> > > RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169
> > > RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c
> > > RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000
> > > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> > > R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8
> > > </TASK>
> > >
> > > Allocated by task 10025:
> > > kasan_save_stack mm/kasan/common.c:47 [inline]
> > > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> > > poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
> > > __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
> > > kasan_kmalloc include/linux/kasan.h:260 [inline]
> > > __do_kmalloc_node mm/slub.c:4294 [inline]
> > > __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313
> > > __kmemdup_nul mm/util.c:61 [inline]
> > > kstrdup+0x42/0x100 mm/util.c:81
> > > kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274
> > > dev_set_name+0xd5/0x120 drivers/base/core.c:3468
> > > assign_name drivers/infiniband/core/device.c:1202 [inline]
> > > ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384
> > > rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
> > > rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
> > > rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
> > > nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
> > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> > > sock_sendmsg_nosec net/socket.c:709 [inline]
> > > __sock_sendmsg+0x221/0x270 net/socket.c:724
> > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> > > ___sys_sendmsg net/socket.c:2618 [inline]
> > > __sys_sendmsg+0x269/0x350 net/socket.c:2650
> > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> > > entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > >
> > > Freed by task 10035:
> > > kasan_save_stack mm/kasan/common.c:47 [inline]
> > > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> > > kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> > > poison_slab_object mm/kasan/common.c:247 [inline]
> > > __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> > > kasan_slab_free include/linux/kasan.h:233 [inline]
> > > slab_free_hook mm/slub.c:2353 [inline]
> > > slab_free mm/slub.c:4609 [inline]
> > > kfree+0x196/0x430 mm/slub.c:4757
> > > kobject_rename+0x38f/0x410 lib/kobject.c:524
> > > device_rename+0x16a/0x200 drivers/base/core.c:4525
> > > ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402
> > > nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146
> > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
> > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> > > sock_sendmsg_nosec net/socket.c:709 [inline]
> > > __sock_sendmsg+0x221/0x270 net/socket.c:724
> > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> > > ___sys_sendmsg net/socket.c:2618 [inline]
> > > __sys_sendmsg+0x269/0x350 net/socket.c:2650
> > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> > > entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > >
> > > This is because if rename device happens, the old name is freed in
> > > ib_device_rename() with lock, but fill_nldev_handle() may visit the dev
> > > name locklessly triggered by rxe_newlink().
> > >
> > > Fix this by add lock around rdma_nl_notify_event() in
> > > ib_device_notify_register().
> > >
> > > Reported-by: syzbot+f60349ba1f9f08df349f@syzkaller.appspotmail.com
> > > Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8
> > > Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring")
> > > Signed-off-by: Wang Liang <wangliang74@huawei.com>
> > > ---
> > > drivers/infiniband/core/device.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> > > index 0ded91f056f3..4536621ada0d 100644
> > > --- a/drivers/infiniband/core/device.c
> > > +++ b/drivers/infiniband/core/device.c
> > > @@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device)
> > > u32 port;
> > > int ret;
> > > + down_write(&devices_rwsem);
> > The analysis looks correct to me, however this should be down_read(&devices_rwsem)
> > together with comment about possible race with RDMA netlink, which can change
> > internals of struct ib_device.
> >
> > I wonder if this read semaphore should be hold for whole
> > ib_device_notify_register() function and not only for RDMA_REGISTER_EVENT event.
> >
> > Thanks
> Yes, you are right! The RDMA_NETDEV_ATTACH_EVENT event in function
> ib_device_notify_register() can also visit the dev name locklessly:
>
> rxe_newlink
> ...
> ib_device_notify_register
> rdma_nl_notify_event(RDMA_NETDEV_ATTACH_EVENT)
> fill_mon_netdev_association
> // visit dev_name without devices_rwsem
>
> What's more, the following trace may also trigger the issue when function
> nldev_set_doit() rename device:
>
> (1)
> RDMA_NLDEV_CMD_GET
> nldev_get_doit
> fill_dev_info
> fill_nldev_handle
> // visit dev_name without devices_rwsem
>
> (2)
> RDMA_NLDEV_CMD_PORT_GET
> nldev_port_get_doit
> fill_port_info
> fill_nldev_handle
> // visit dev_name without devices_rwsem
>
> (3)
> RDMA_NLDEV_CMD_RES_GET
> nldev_res_get_doit
> fill_res_info
> fill_nldev_handle
> // visit dev_name without devices_rwsem
>
> And more...
>
> However, some scenarios hold devices_rwsem, like function
> nldev_get_dumpit(),
> which was modified by 921eab1143aa("RDMA/devices: Re-organize device.c
> locking"):
>
> RDMA_NLDEV_CMD_GET
> nldev_get_dumpit
> ib_enum_all_devs
> down_read(&devices_rwsem); // hold devices_rwsem read
> _nldev_get_dumpit
> fill_dev_info
> fill_nldev_handle
> // visit dev_name with devices_rwsem
> up_read(&devices_rwsem);
>
> So only hold devices_rwsem for whole ib_device_notify_register() may be not
> enough.
>
> How about add down_read(&devices_rwsem) around
> fill_dev_info()/fill_port_info()/
> fill_res_info()/ib_device_notify_register().
I don't think so, as all flows in nldev.c except rdma_nl_notify_event() are
single threaded and call to ib_device_rename() will make sure that no
other RDMA_NLDEV_CMD_* commands are executed.
In your case call to rdma_nl_notify_event() can happen in parallel to
device_rename only.
Thanks
在 2025/3/12 21:49, Leon Romanovsky 写道:
> On Tue, Mar 11, 2025 at 10:55:42AM +0800, Wang Liang wrote:
>> 在 2025/3/10 18:14, Leon Romanovsky 写道:
>>> On Mon, Mar 10, 2025 at 02:45:16PM +0800, Wang Liang wrote:
>>>> Syzbot reported a slab-use-after-free with the following call trace:
>>>>
>>>> ==================================================================
>>>> BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099
>>>> Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025
>>>>
>>>> CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
>>>> Hardware name: Google Compute Engine, BIOS Google 02/12/2025
>>>> Call Trace:
>>>> <TASK>
>>>> __dump_stack lib/dump_stack.c:94 [inline]
>>>> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>>>> print_address_description mm/kasan/report.c:408 [inline]
>>>> print_report+0x16e/0x5b0 mm/kasan/report.c:521
>>>> kasan_report+0x143/0x180 mm/kasan/report.c:634
>>>> kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
>>>> __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
>>>> nla_put+0xd3/0x150 lib/nlattr.c:1099
>>>> nla_put_string include/net/netlink.h:1621 [inline]
>>>> fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265
>>>> rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857
>>>> ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344
>>>> ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460
>>>> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
>>>> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
>>>> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
>>>> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
>>>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>>>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>>>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>>>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>>>> sock_sendmsg_nosec net/socket.c:709 [inline]
>>>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>>>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>>>> ___sys_sendmsg net/socket.c:2618 [inline]
>>>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>>> RIP: 0033:0x7f42d1b8d169
>>>> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ...
>>>> RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>>>> RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169
>>>> RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c
>>>> RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000
>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
>>>> R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8
>>>> </TASK>
>>>>
>>>> Allocated by task 10025:
>>>> kasan_save_stack mm/kasan/common.c:47 [inline]
>>>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>>>> poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
>>>> __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
>>>> kasan_kmalloc include/linux/kasan.h:260 [inline]
>>>> __do_kmalloc_node mm/slub.c:4294 [inline]
>>>> __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313
>>>> __kmemdup_nul mm/util.c:61 [inline]
>>>> kstrdup+0x42/0x100 mm/util.c:81
>>>> kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274
>>>> dev_set_name+0xd5/0x120 drivers/base/core.c:3468
>>>> assign_name drivers/infiniband/core/device.c:1202 [inline]
>>>> ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384
>>>> rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540
>>>> rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550
>>>> rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212
>>>> nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795
>>>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>>>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>>>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>>>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>>>> sock_sendmsg_nosec net/socket.c:709 [inline]
>>>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>>>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>>>> ___sys_sendmsg net/socket.c:2618 [inline]
>>>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>>>
>>>> Freed by task 10035:
>>>> kasan_save_stack mm/kasan/common.c:47 [inline]
>>>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>>>> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
>>>> poison_slab_object mm/kasan/common.c:247 [inline]
>>>> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
>>>> kasan_slab_free include/linux/kasan.h:233 [inline]
>>>> slab_free_hook mm/slub.c:2353 [inline]
>>>> slab_free mm/slub.c:4609 [inline]
>>>> kfree+0x196/0x430 mm/slub.c:4757
>>>> kobject_rename+0x38f/0x410 lib/kobject.c:524
>>>> device_rename+0x16a/0x200 drivers/base/core.c:4525
>>>> ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402
>>>> nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146
>>>> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>>>> rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259
>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>>>> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
>>>> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
>>>> sock_sendmsg_nosec net/socket.c:709 [inline]
>>>> __sock_sendmsg+0x221/0x270 net/socket.c:724
>>>> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
>>>> ___sys_sendmsg net/socket.c:2618 [inline]
>>>> __sys_sendmsg+0x269/0x350 net/socket.c:2650
>>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>>>
>>>> This is because if rename device happens, the old name is freed in
>>>> ib_device_rename() with lock, but fill_nldev_handle() may visit the dev
>>>> name locklessly triggered by rxe_newlink().
>>>>
>>>> Fix this by add lock around rdma_nl_notify_event() in
>>>> ib_device_notify_register().
>>>>
>>>> Reported-by: syzbot+f60349ba1f9f08df349f@syzkaller.appspotmail.com
>>>> Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8
>>>> Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring")
>>>> Signed-off-by: Wang Liang <wangliang74@huawei.com>
>>>> ---
>>>> drivers/infiniband/core/device.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
>>>> index 0ded91f056f3..4536621ada0d 100644
>>>> --- a/drivers/infiniband/core/device.c
>>>> +++ b/drivers/infiniband/core/device.c
>>>> @@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device)
>>>> u32 port;
>>>> int ret;
>>>> + down_write(&devices_rwsem);
>>> The analysis looks correct to me, however this should be down_read(&devices_rwsem)
>>> together with comment about possible race with RDMA netlink, which can change
>>> internals of struct ib_device.
>>>
>>> I wonder if this read semaphore should be hold for whole
>>> ib_device_notify_register() function and not only for RDMA_REGISTER_EVENT event.
>>>
>>> Thanks
>> Yes, you are right! The RDMA_NETDEV_ATTACH_EVENT event in function
>> ib_device_notify_register() can also visit the dev name locklessly:
>>
>> ......
>>
>> So only hold devices_rwsem for whole ib_device_notify_register() may be not
>> enough.
>>
>> How about add down_read(&devices_rwsem) around
>> fill_dev_info()/fill_port_info()/
>> fill_res_info()/ib_device_notify_register().
> I don't think so, as all flows in nldev.c except rdma_nl_notify_event() are
> single threaded and call to ib_device_rename() will make sure that no
> other RDMA_NLDEV_CMD_* commands are executed.
>
> In your case call to rdma_nl_notify_event() can happen in parallel to
> device_rename only.
>
> Thanks
Thanks for all your comments.
I will send a new patch later, and hold the devices_rwsem for whole
ib_device_notify_register().
Please check it. Thanks.
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