linux-kernel - Re: [PATCH v3] staging: r8188eu: Use kzalloc() with GFP

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Message-ID: <20211105132551.GB2001@kadam>
Date:   Fri, 5 Nov 2021 16:25:52 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Cc:     Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in
 atomic context

On Mon, Nov 01, 2021 at 08:18:47PM +0100, Fabio M. De Francesco wrote:
> Use the GFP_ATOMIC flag of kzalloc() with two memory allocation in
> report_del_sta_event(). This function is called while holding spinlocks,
> therefore it is not allowed to sleep. With the GFP_ATOMIC type flag, the
> allocation is high priority and must not sleep.
> 
> This issue is detected by Smatch which emits the following warning:
> "drivers/staging/r8188eu/core/rtw_mlme_ext.c:6848 report_del_sta_event()
> warn: sleeping in atomic context".
> 
> After the change, the post-commit hook output the following message:
> "CHECK: Prefer kzalloc(sizeof(*pcmd_obj)...) over
> kzalloc(sizeof(struct cmd_obj)...)".
> 
> According to the above "CHECK", use the preferred style in the first
> kzalloc().
> 
> Fixes: 79f712ea994d ("staging: r8188eu: Remove wrappers for kalloc() and kzalloc()")

This is not the correct Fixes tag.  The original allocation wrappers
checked in_interrupt() they did not check in_atomic() so they had same
bug.  The correct tag is:

Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")

regards,
dan carpenter