[PATCH v2] staging: zcache: fix possible sleep under lock
Dan Magenheimer
dan.magenheimer at oracle.com
Tue Aug 23 15:18:25 UTC 2011
> From: Seth Jennings [mailto:sjenning at linux.vnet.ibm.com]
> Sent: Monday, August 22, 2011 1:31 PM
> To: gregkh at suse.de
> Cc: ascardo at holoscopio.com; Dan Magenheimer; sjenning at linux.vnet.ibm.com; rdunlap at xenotime.net;
> devel at driverdev.osuosl.org; linux-kernel at vger.kernel.org
> Subject: [PATCH v2] staging: zcache: fix possible sleep under lock
>
> zcache_new_pool() calls kmalloc() with GFP_KERNEL which has
> __GFP_WAIT set. However, zcache_new_pool() gets called on
> a stack that holds the swap_lock spinlock, leading to a
> possible sleep-with-lock situation. The lock is obtained
> in enable_swap_info().
>
> The patch replaces GFP_KERNEL with GFP_ATOMIC.
>
> v2: replace with GFP_ATOMIC, not GFP_IOFS
>
> Signed-off-by: Seth Jennings <sjenning at linux.vnet.ibm.com>
Acked-by: Dan Magenheimer <dan.magenheimer at oracle.com>
> ---
> drivers/staging/zcache/zcache-main.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
> index 855a5bb..cdf0128 100644
> --- a/drivers/staging/zcache/zcache-main.c
> +++ b/drivers/staging/zcache/zcache-main.c
> @@ -1668,7 +1668,7 @@ static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
> if (cli == NULL)
> goto out;
> atomic_inc(&cli->refcount);
> - pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
> + pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
> if (pool == NULL) {
> pr_info("zcache: pool creation failed: out of memory\n");
> goto out;
> --
> 1.7.4.1
>
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