linux-kernel - [PATCH 4.9 52/61] stm class: Use vmalloc for the master map

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Date:   Tue,  5 Jun 2018 19:02:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Fengguang Wu <fengguang.wu@...el.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Subject: [PATCH 4.9 52/61] stm class: Use vmalloc for the master map

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>

commit b5e2ced9bf81393034072dd4d372f6b430bc1f0a upstream.

Fengguang is running into a warning from the buddy allocator:

> swapper/0: page allocation failure: order:9, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
> CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.17.0-rc1 #262
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> Call Trace:
...
>  __kmalloc+0x14b/0x180: ____cache_alloc at mm/slab.c:3127
>  stm_register_device+0xf3/0x5c0: stm_register_device at drivers/hwtracing/stm/core.c:695
...

Which is basically a result of the stm class trying to allocate ~512kB
for the dummy_stm with its default parameters. There's no reason, however,
for it not to be vmalloc()ed instead, which is what this patch does.

Reported-by: Fengguang Wu <fengguang.wu@...el.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
CC: stable@...r.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/hwtracing/stm/core.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -682,7 +682,7 @@ static void stm_device_release(struct de
 {
 	struct stm_device *stm = to_stm_device(dev);
 
-	kfree(stm);
+	vfree(stm);
 }
 
 int stm_register_device(struct device *parent, struct stm_data *stm_data,
@@ -699,7 +699,7 @@ int stm_register_device(struct device *p
 		return -EINVAL;
 
 	nmasters = stm_data->sw_end - stm_data->sw_start + 1;
-	stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
+	stm = vzalloc(sizeof(*stm) + nmasters * sizeof(void *));
 	if (!stm)
 		return -ENOMEM;
 
@@ -752,7 +752,7 @@ err_device:
 	/* matches device_initialize() above */
 	put_device(&stm->dev);
 err_free:
-	kfree(stm);
+	vfree(stm);
 
 	return err;
 }