Thanks your reviewing @Guoqing
> Thanks for the fix, it would be better to comment that why kobject_del can't
> be called here.
commmit f7452a7e96c1 ("RDMA/rtrs-srv: fix memory leak by missing kobject free")
memtioned a free_sess(), but i didn't get it exactly(no such function ?). So i have
not sorted it out.
And hold on，with below change， kernel gets another WARNING.
I'm still working on it.
[ 125.034407] =========================
[ 125.035490] WARNING: held lock freed!
[ 125.036640] 6.2.0-rc6-roce-flush+ #53 Not tainted
[ 125.038088] -------------------------
[ 125.039143] kworker/0:3/63 is freeing memory ffff90bd01eaa000-ffff90bd01eaa7ff, with a lock still held there!
[ 125.041660] ffff90bd01eaa118 (&srv->paths_mutex){+.+.}-{3:3}, at: rtrs_srv_destroy_once_sysfs_root_folders.isra.0+0x24/0x60 [rtrs_server]
[ 125.044600] 3 locks held by kworker/0:3/63:
[ 125.046091] #0: ffff90bd05f8ed38 ((wq_completion)rtrs_server_wq){+.+.}-{0:0}, at: process_one_work+0x1f4/0x590
[ 125.048876] #1: ffff9ff4c085fe78 ((work_completion)(&srv_path->close_work)){+.+.}-{0:0}, at: process_one_work+0x1f4/0x590
[ 125.051789] #2: ffff90bd01eaa118 (&srv->paths_mutex){+.+.}-{3:3}, at: rtrs_srv_destroy_once_sysfs_root_folders.isra.0+0x24/0x60 [rtrs_server]
[ 125.055167]
[ 125.055167] stack backtrace:
[ 125.057979] CPU: 0 PID: 63 Comm: kworker/0:3 Kdump: loaded Not tainted 6.2.0-rc6-roce-flush+ #53
[ 125.060201] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[ 125.063156] Workqueue: rtrs_server_wq rtrs_srv_close_work [rtrs_server]
[ 125.065031] Call Trace:
[ 125.065905] <TASK>
[ 125.066733] dump_stack_lvl+0x45/0x5d
[ 125.068003] debug_check_no_locks_freed.cold+0x77/0x7c
[ 125.069565] ? device_release+0x34/0x90
[ 125.070814] __kmem_cache_free+0x74/0x190
[ 125.072059] device_release+0x34/0x90
[ 125.073203] kobject_put+0x8b/0x1d0
[ 125.074385] rtrs_srv_destroy_once_sysfs_root_folders.isra.0+0x35/0x60 [rtrs_server]
[ 125.076456] rtrs_srv_close_work+0x21/0x270 [rtrs_server]
[ 125.078097] process_one_work+0x274/0x590
[ 125.079372] worker_thread+0x4f/0x3d0
[ 125.080508] ? __pfx_worker_thread+0x10/0x10
[ 125.081751] kthread+0xe7/0x110
[ 125.082778] ? __pfx_kthread+0x10/0x10
[ 125.083894] ret_from_fork+0x2c/0x50
[ 125.084991] </TASK>
On 02/02/2023 09:41, Guoqing Jiang wrote:
>
>
> On 2/1/23 22:30, Li Zhijian wrote:
>> As the mention in commmit f7452a7e96c1 ("RDMA/rtrs-srv: fix memory leak by missing kobject free"),
>> it's intended to remove the kobject_del for srv_path->kobj.
>>
>> A kernel panic will be triggered by following script
>> -----------------------
>> $ while true;
>> do
>> echo "sessname=foo path=ip:<ip address> device_path=/dev/nvme0n1" > /sys/devices/virtual/rnbd-client/ctl/map_device
>> echo "normal" > /sys/block/rnbd0/rnbd/unmap_device
>> done
>> -----------------------
>> The bisection pointed to commit 6af4609c18b3 ("RDMA/rtrs-srv: Fix several issues in rtrs_srv_destroy_path_files")
>> at last.
>>
>> rnbd_server L777: </dev/nvme0n1@foo>: Opened device 'nvme0n1'
>> general protection fault, probably for non-canonical address 0x765f766564753aea: 0000 [#1] PREEMPT SMP PTI
>> CPU: 0 PID: 3558 Comm: systemd-udevd Kdump: loaded Not tainted 6.1.0-rc3-roce-flush+ #51
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
>> RIP: 0010:kernfs_dop_revalidate+0x36/0x180
>> Code: 00 00 41 55 41 54 55 53 48 8b 47 68 48 89 fb 48 85 c0 0f 84 db 00 00 00 48 8b a8 60 04 00 00 48 8b 45 30 48 85 c0 48 0f 44 c5 <4c> 8b 60 78 49 81 c4 d8 00 00 00 4c 89 e7 e8 b7 78 7b 00 8b 05 3d
>> RSP: 0018:ffffaf1700b67c78 EFLAGS: 00010206
>> RAX: 765f766564753a72 RBX: ffff89e2830849c0 RCX: 0000000000000000
>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff89e2830849c0
>> RBP: ffff89e280361bd0 R08: 0000000000000000 R09: 0000000000000001
>> R10: 0000000000000065 R11: 0000000000000000 R12: ffff89e2830849c0
>> R13: ffff89e283084888 R14: d0d0d0d0d0d0d0d0 R15: 2f2f2f2f2f2f2f2f
>> FS: 00007f13fbce7b40(0000) GS:ffff89e2bbc00000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f93e055d340 CR3: 0000000104664002 CR4: 00000000001706f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> lookup_fast+0x7b/0x100
>> walk_component+0x21/0x160
>> link_path_walk.part.0+0x24d/0x390
>> path_openat+0xad/0x9a0
>> do_filp_open+0xa9/0x150
>> ? lock_release+0x13c/0x2e0
>> ? _raw_spin_unlock+0x29/0x50
>> ? alloc_fd+0x124/0x1f0
>> do_sys_openat2+0x9b/0x160
>> __x64_sys_openat+0x54/0xa0
>> do_syscall_64+0x3b/0x90
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> RIP: 0033:0x7f13fc9d701b
>> Code: 25 00 00 41 00 3d 00 00 41 00 74 4b 64 8b 04 25 18 00 00 00 85 c0 75 67 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 91 00 00 00 48 8b 54 24 28 64 48 2b 14 25
>> RSP: 002b:00007ffddf242640 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f13fc9d701b
>> RDX: 0000000000080000 RSI: 00007ffddf2427c0 RDI: 00000000ffffff9c
>> RBP: 00007ffddf2427c0 R08: 00007f13fcc5b440 R09: 21b2131aa64b1ef2
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
>> R13: 00007ffddf2427c0 R14: 000055ed13be8db0 R15: 0000000000000000
>>
>> Fixes: 6af4609c18b3 ("RDMA/rtrs-srv: Fix several issues in rtrs_srv_destroy_path_files")
>> Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
>> ---
>> drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c b/drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c
>> index da8e205ce331..7fe905424109 100644
>> --- a/drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c
>> +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c
>> @@ -313,7 +313,6 @@ void rtrs_srv_destroy_path_files(struct rtrs_srv_path *srv_path)
>> if (srv_path->kobj.state_in_sysfs) {
>> sysfs_remove_group(&srv_path->kobj, &rtrs_srv_path_attr_group);
>> - kobject_del(&srv_path->kobj);
>> kobject_put(&srv_path->kobj);
>> }
>
> Thanks for the fix, it would be better to comment that why kobject_del can't
> be called here.
>
> Anyway, Acked-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
>
> Thanks,
> Guoqing
