linux-kernel - Re: [PATCH] scsi: target: tcm_loop: fix segfault in tcm_loop_tpg_address

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Message-ID: <176283044352.2802267.12286632671055690228.b4-ty@oracle.com>
Date: Wed, 12 Nov 2025 21:47:27 -0500
From: "Martin K. Petersen" <martin.petersen@...cle.com>
To: linux-kernel@...r.kernel.org,
        Hamza Mahfooz <hamzamahfooz@...ux.microsoft.com>
Cc: "Martin K . Petersen" <martin.petersen@...cle.com>,
        Guixin Liu <kanie@...ux.alibaba.com>,
        Nicholas Bellinger <nab@...ux-iscsi.org>,
        Sheng Yang <sheng@...ker.org>, linux-scsi@...r.kernel.org,
        target-devel@...r.kernel.org, Allen Pais <apais@...ux.microsoft.com>,
        stable@...r.kernel.org
Subject: Re: [PATCH] scsi: target: tcm_loop: fix segfault in tcm_loop_tpg_address_show()

On Wed, 05 Nov 2025 11:25:46 -0800, Hamza Mahfooz wrote:

> If the allocation of tl_hba->sh fails in tcm_loop_driver_probe() and we
> attempt to dereference it in tcm_loop_tpg_address_show() we will get a
> segfault, see below for an example. So, check tl_hba->sh before
> dereferencing it.
> 
>   Unable to allocate struct scsi_host
>   BUG: kernel NULL pointer dereference, address: 0000000000000194
>   #PF: supervisor read access in kernel mode
>   #PF: error_code(0x0000) - not-present page
>   PGD 0 P4D 0
>   Oops: 0000 [#1] PREEMPT SMP NOPTI
>   CPU: 1 PID: 8356 Comm: tokio-runtime-w Not tainted 6.6.104.2-4.azl3 #1
>   Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/28/2024
>   RIP: 0010:tcm_loop_tpg_address_show+0x2e/0x50 [tcm_loop]
> ...
>   Call Trace:
>    <TASK>
>    configfs_read_iter+0x12d/0x1d0 [configfs]
>    vfs_read+0x1b5/0x300
>    ksys_read+0x6f/0xf0
> ...
> 
> [...]

Applied to 6.18/scsi-fixes, thanks!

[1/1] scsi: target: tcm_loop: fix segfault in tcm_loop_tpg_address_show()
      https://git.kernel.org/mkp/scsi/c/e6965188f84a

-- 
Martin K. Petersen