linux-kernel - RE: [PATCH] megaraid: Fix a sleep-in-atomic bug

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Message-ID: <ecd2b8137043d6c6b75c4f44b963bebd@mail.gmail.com>
Date:   Wed, 31 May 2017 15:48:03 +0530
From:   Sumit Saxena <sumit.saxena@...adcom.com>
To:     Jia-Ju Bai <baijiaju1990@....com>,
        Kashyap Desai <kashyap.desai@...adcom.com>,
        Shivasharan Srikanteshwara 
        <shivasharan.srikanteshwara@...adcom.com>, jejb@...ux.vnet.ibm.com,
        martin.petersen@...cle.com
Cc:     "PDL,MEGARAIDLINUX" <megaraidlinux.pdl@...adcom.com>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: RE: [PATCH] megaraid: Fix a sleep-in-atomic bug

>-----Original Message-----
>From: Jia-Ju Bai [mailto:baijiaju1990@....com]
>Sent: Wednesday, May 31, 2017 8:27 AM
>To: kashyap.desai@...adcom.com; sumit.saxena@...adcom.com;
>shivasharan.srikanteshwara@...adcom.com; jejb@...ux.vnet.ibm.com;
>martin.petersen@...cle.com
>Cc: megaraidlinux.pdl@...adcom.com; linux-scsi@...r.kernel.org; linux-
>kernel@...r.kernel.org; Jia-Ju Bai
>Subject: [PATCH] megaraid: Fix a sleep-in-atomic bug
>
>The driver may sleep under a spin lock, and the function call path is:
>mraid_mm_attach_buf (acquire the lock by spin_lock_irqsave)
>  pci_pool_alloc(GFP_KERNEL) --> may sleep
>
>To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".
>
>Signed-off-by: Jia-Ju Bai <baijiaju1990@....com>
>---
> drivers/scsi/megaraid/megaraid_mm.c |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/scsi/megaraid/megaraid_mm.c
>b/drivers/scsi/megaraid/megaraid_mm.c
>index 4cf9ed9..c43afb8 100644
>--- a/drivers/scsi/megaraid/megaraid_mm.c
>+++ b/drivers/scsi/megaraid/megaraid_mm.c
>@@ -574,7 +574,7 @@
>
> 	kioc->pool_index	= right_pool;
> 	kioc->free_buf		= 1;
>-	kioc->buf_vaddr 	= pci_pool_alloc(pool->handle, GFP_KERNEL,
>+	kioc->buf_vaddr 	= pci_pool_alloc(pool->handle, GFP_ATOMIC,
> 							&kioc->buf_paddr);
> 	spin_unlock_irqrestore(&pool->lock, flags);

This is very old driver and reached EOL. Did you face any issue because of
this bug or discover this through code review?
Anyways patch looks good to me.

Acked-by: Sumit Saxena <sumit.saxena@...adcom.com>

>
>--
>1.7.9.5
>