linux-kernel - Re: [PATCH mlx5-next 1/7] RDMA/mlx5: Don't set esc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <fdae8091-337d-a21d-d31d-5270e5029bb8@nvidia.com>
Date:   Tue, 12 Oct 2021 16:57:16 +0300
From:   Aharon Landau <aharonl@...dia.com>
To:     Jason Gunthorpe <jgg@...dia.com>, Leon Romanovsky <leon@...nel.org>
Cc:     Doug Ledford <dledford@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Jason Wang <jasowang@...hat.com>, linux-kernel@...r.kernel.org,
        linux-rdma@...r.kernel.org, Maor Gottlieb <maorg@...dia.com>,
        "Michael S. Tsirkin" <mst@...hat.com>, netdev@...r.kernel.org,
        Saeed Mahameed <saeedm@...dia.com>,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH mlx5-next 1/7] RDMA/mlx5: Don't set esc_size in user mr


On 10/12/2021 3:52 PM, Jason Gunthorpe wrote:
> On Tue, Oct 12, 2021 at 01:26:29PM +0300, Leon Romanovsky wrote:
>> From: Aharon Landau <aharonl@...dia.com>
>>
>> reg_create() is used for user MRs only and should not set desc_size at
>> all. Attempt to set it causes to the following trace:
>>
>> BUG: unable to handle page fault for address: 0000000800000000
>> PGD 0 P4D 0
>> Oops: 0000 [#1] SMP PTI
>> CPU: 5 PID: 890 Comm: ib_write_bw Not tainted 5.15.0-rc4+ #47
>> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
>> RIP: 0010:mlx5_ib_dereg_mr+0x14/0x3b0 [mlx5_ib]
>> Code: 48 63 cd 4c 89 f7 48 89 0c 24 e8 37 30 03 e1 48 8b 0c 24 eb a0 90 0f 1f 44 00 00 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 30 <48> 8b 2f 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 31 c0 8b 87 c8
>> RSP: 0018:ffff88811afa3a60 EFLAGS: 00010286
>> RAX: 000000000000001c RBX: 0000000800000000 RCX: 0000000000000000
>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000800000000
>> RBP: 0000000800000000 R08: 0000000000000000 R09: c0000000fffff7ff
>> R10: ffff88811afa38f8 R11: ffff88811afa38f0 R12: ffffffffa02c7ac0
>> R13: 0000000000000000 R14: ffff88811afa3cd8 R15: ffff88810772fa00
>> FS:  00007f47b9080740(0000) GS:ffff88852cd40000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000800000000 CR3: 000000010761e003 CR4: 0000000000370ea0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>>   mlx5_ib_free_odp_mr+0x95/0xc0 [mlx5_ib]
>>   mlx5_ib_dereg_mr+0x128/0x3b0 [mlx5_ib]
>>   ib_dereg_mr_user+0x45/0xb0 [ib_core]
>>   ? xas_load+0x8/0x80
>>   destroy_hw_idr_uobject+0x1a/0x50 [ib_uverbs]
>>   uverbs_destroy_uobject+0x2f/0x150 [ib_uverbs]
>>   uobj_destroy+0x3c/0x70 [ib_uverbs]
>>   ib_uverbs_cmd_verbs+0x467/0xb00 [ib_uverbs]
>>   ? uverbs_finalize_object+0x60/0x60 [ib_uverbs]
>>   ? ttwu_queue_wakelist+0xa9/0xe0
>>   ? pty_write+0x85/0x90
>>   ? file_tty_write.isra.33+0x214/0x330
>>   ? process_echoes+0x60/0x60
>>   ib_uverbs_ioctl+0xa7/0x110 [ib_uverbs]
>>   __x64_sys_ioctl+0x10d/0x8e0
>>   ? vfs_write+0x17f/0x260
>>   do_syscall_64+0x3c/0x80
>>   entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> Fixes: a639e66703ee ("RDMA/mlx5: Zero out ODP related items in the mlx5_ib_mr")
> Can you explain why this is crashing?
>
> reg_create isn't used on the ODP implicit children path.
>
> Jason
It is not implicit ODP flow, therefore, mr->implicit_children shouldn't 
be set.

desc_size shares the same union with implicit_children, and setting it 
leads to a wrong iteration.

Aharon