Re: [PATCH] regmap: rbtree: Use alloc_flags for memory allocations

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Jul 21, 2023 at 05:55:33PM +0300, Dan Carpenter wrote:
> The kunit tests discovered a sleeping in atomic bug.  The allocations
> in the regcache-rbtree code should use the map->alloc_flags instead of
> GFP_KERNEL.
> 
> [    5.005510] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
> [    5.005960] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 117, name: kunit_try_catch
> [    5.006219] preempt_count: 1, expected: 0
> [    5.006414] 1 lock held by kunit_try_catch/117:
> [    5.006590]  #0: 833b9010 (regmap_kunit:86:(config)->lock){....}-{2:2}, at: regmap_lock_spinlock+0x14/0x1c
> [    5.007493] irq event stamp: 162
> [    5.007627] hardirqs last  enabled at (161): [<80786738>] crng_make_state+0x1a0/0x294
> [    5.007871] hardirqs last disabled at (162): [<80c531ec>] _raw_spin_lock_irqsave+0x7c/0x80
> [    5.008119] softirqs last  enabled at (0): [<801110ac>] copy_process+0x810/0x2138
> [    5.008356] softirqs last disabled at (0): [<00000000>] 0x0
> [    5.008688] CPU: 0 PID: 117 Comm: kunit_try_catch Tainted: G                 N 6.4.4-rc3-g0e8d2fdfb188 #1
> [    5.009011] Hardware name: Generic DT based system
> [    5.009277]  unwind_backtrace from show_stack+0x18/0x1c
> [    5.009497]  show_stack from dump_stack_lvl+0x38/0x5c
> [    5.009676]  dump_stack_lvl from __might_resched+0x188/0x2d0
> [    5.009860]  __might_resched from __kmem_cache_alloc_node+0x1dc/0x25c
> [    5.010061]  __kmem_cache_alloc_node from kmalloc_trace+0x30/0xc8
> [    5.010254]  kmalloc_trace from regcache_rbtree_write+0x26c/0x468
> [    5.010446]  regcache_rbtree_write from _regmap_write+0x88/0x140
> [    5.010634]  _regmap_write from regmap_write+0x44/0x68
> [    5.010803]  regmap_write from basic_read_write+0x8c/0x270
> [    5.010980]  basic_read_write from kunit_try_run_case+0x48/0xa0
> 
> Fixes: 28644c809f44 ("regmap: Add the rbtree cache support")
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Closes: https://lore.kernel.org/all/ee59d128-413c-48ad-a3aa-d9d350c80042@roeck-us.net/
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
> This patch is similar to what I sent earlier, but I changed
> regcache_rbtree_init() back to using GFP_KERNEL.
> 
>  drivers/base/regmap/regcache-rbtree.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
> index fabf87058d80..ae6b8788d5f3 100644
> --- a/drivers/base/regmap/regcache-rbtree.c
> +++ b/drivers/base/regmap/regcache-rbtree.c
> @@ -277,7 +277,7 @@ static int regcache_rbtree_insert_to_block(struct regmap *map,
>  
>  	blk = krealloc(rbnode->block,
>  		       blklen * map->cache_word_size,
> -		       GFP_KERNEL);
> +		       map->alloc_flags);
>  	if (!blk)
>  		return -ENOMEM;
>  
> @@ -286,7 +286,7 @@ static int regcache_rbtree_insert_to_block(struct regmap *map,
>  	if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) {
>  		present = krealloc(rbnode->cache_present,
>  				   BITS_TO_LONGS(blklen) * sizeof(*present),
> -				   GFP_KERNEL);
> +				   map->alloc_flags);
>  		if (!present)
>  			return -ENOMEM;
>  
> @@ -320,7 +320,7 @@ regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
>  	const struct regmap_range *range;
>  	int i;
>  
> -	rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL);
> +	rbnode = kzalloc(sizeof(*rbnode), map->alloc_flags);
>  	if (!rbnode)
>  		return NULL;
>  
> @@ -346,13 +346,13 @@ regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
>  	}
>  
>  	rbnode->block = kmalloc_array(rbnode->blklen, map->cache_word_size,
> -				      GFP_KERNEL);
> +				      map->alloc_flags);
>  	if (!rbnode->block)
>  		goto err_free;
>  
>  	rbnode->cache_present = kcalloc(BITS_TO_LONGS(rbnode->blklen),
>  					sizeof(*rbnode->cache_present),
> -					GFP_KERNEL);
> +					map->alloc_flags);
>  	if (!rbnode->cache_present)
>  		goto err_free_block;
>  
> -- 
> 2.39.2
>