From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lazybastard.de ([212.112.238.170] helo=longford.logfs.org) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1Ja6ZJ-000289-Kr for linux-mtd@lists.infradead.org; Fri, 14 Mar 2008 09:51:18 +0000 Date: Fri, 14 Mar 2008 09:52:13 +0100 From: =?utf-8?B?SsO2cm4=?= Engel To: Anton Vorontsov Subject: Re: [PATCH] mtd: maps/physmap: fix oops in suspend/resume/shutdown ops Message-ID: <20080314085213.GA12178@logfs.org> References: <20080217213734.GA4091@zarina> <20080314005209.GA13563@zarina> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20080314005209.GA13563@zarina> Cc: linux-mtd@lists.infradead.org, dwmw2@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 14 March 2008 03:52:09 +0300, Anton Vorontsov wrote: > On Mon, Feb 18, 2008 at 12:37:34AM +0300, Anton Vorontsov wrote: > > - - - - > > # reboot > > ... > > [ 42.351266] Flash device refused suspend due to active operation (state 0) > > [ 42.358195] Unable to handle kernel NULL pointer dereference at virtual address 00000078 > > [ 42.360060] pgd = c7d9c000 > > [ 42.362769] [00000078] *pgd=a7d8d031, *pte=00000000, *ppte=00000000 > > [ 42.372902] Internal error: Oops: 17 [#1] > > [ 42.376911] Modules linked in: > > [ 42.379980] CPU: 0 Not tainted (2.6.25-rc2-10642-ge8f2594-dirty #73) > > [ 42.380000] PC is at physmap_flash_shutdown+0x28/0x54 > > ... > > [ 42.380000] Backtrace: > > [ 42.380000] [] (physmap_flash_shutdown+0x0/0x54) from [] (platform_drv_shutdown+0x20/0x24) > > [ 42.380000] r5:28121969 r4:c0229e08 > > [ 42.380000] [] (platform_drv_shutdown+0x0/0x24) from [] (device_shutdown+0x60/0x88) > > [ 42.380000] [] (device_shutdown+0x0/0x88) from [] (kernel_restart_prepare+0x2c/0x3c) > > [ 42.380000] r4:00000000 > > [ 42.380000] [] (kernel_restart_prepare+0x0/0x3c) from [] (kernel_restart+0x14/0x48) > > [ 42.380000] [] (kernel_restart+0x0/0x48) from [] (sys_reboot+0xe8/0x1f8) > > [ 42.380000] r4:01234567 > > [ 42.380000] [] (sys_reboot+0x0/0x1f8) from [] (ret_fast_syscall+0x0/0x2c) > > [ 42.380000] r7:00000058 r6:00000004 r5:00000001 r4:00000000 > > [ 42.380000] Code: 0a000009 e7953004 e1a00003 e1a0e00f (e593f078) > > [ 42.650051] ---[ end trace 6d6c26a0fc3141de ]--- > > Segmentation fault > > INIT: no more processes left in this runlevel > > - - - - > > > > While looping for mtd[i]s, we should stop at the mtd[i] == NULL. > > > > This patch also removes unnecessary "if (info)" checks: > > suspend/resume/shutdown ops are executed only if probe() is succeeded, > > so info is guaranteed to be !NULL. > > > > Signed-off-by: Anton Vorontsov > > --- > > drivers/mtd/maps/physmap.c | 15 +++++++-------- > > 1 files changed, 7 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c > > index f00e04e..bc4649a 100644 > > --- a/drivers/mtd/maps/physmap.c > > +++ b/drivers/mtd/maps/physmap.c > > @@ -202,9 +202,8 @@ static int physmap_flash_suspend(struct platform_device *dev, pm_message_t state > > int ret = 0; > > int i; > > > > - if (info) > > - for (i = 0; i < MAX_RESOURCES; i++) > > - ret |= info->mtd[i]->suspend(info->mtd[i]); > > + for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++) > > + ret |= info->mtd[i]->suspend(info->mtd[i]); > > > > return ret; > > } > > @@ -214,9 +213,9 @@ static int physmap_flash_resume(struct platform_device *dev) > > struct physmap_flash_info *info = platform_get_drvdata(dev); > > int i; > > > > - if (info) > > - for (i = 0; i < MAX_RESOURCES; i++) > > - info->mtd[i]->resume(info->mtd[i]); > > + for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++) > > + info->mtd[i]->resume(info->mtd[i]); > > + > > return 0; > > } > > > > @@ -225,8 +224,8 @@ static void physmap_flash_shutdown(struct platform_device *dev) > > struct physmap_flash_info *info = platform_get_drvdata(dev); > > int i; > > > > - for (i = 0; i < MAX_RESOURCES; i++) > > - if (info && info->mtd[i]->suspend(info->mtd[i]) == 0) > > + for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++) > > + if (info->mtd[i]->suspend(info->mtd[i]) == 0) > > info->mtd[i]->resume(info->mtd[i]); > > } > > #else > > -- > > 1.5.3.7 > > > > Patch seem to be lost. Would be great to get this applied before > final 2.6.25... Ooh! There has been another patch for this problem, but yours is much better. Reviewed-By: Joern Engel David, please apply this instead of Arnaud's or mine. Jörn -- There's nothing better for promoting creativity in a medium than making an audience feel "Hmm ­ I could do better than that!" -- Douglas Adams in a slashdot interview