[PATCH] regmap: fix up the regmap lock error

[PATCH] regmap: fix up the regmap lock error

[Elaine Zhang]

fix up the:
Regmap lock is taken in regmap_update_bits_base() and then
regcache_drop_region() tries to take it again.
which added in commit 815806e39bf6
("regmap: drop cache if the bus transfer error")

Backtrace:
[<8068ab7c>] (__schedule) from [<8068b1c4>] (schedule+0xb8/0xd0)
[<8068b10c>] (schedule) from [<8068b61c>] (schedule_preempt_disabled+0x20/0x2c)
[<8068b5fc>] (schedule_preempt_disabled) from [<8068cd18>] (__mutex_lock_slowpath+0xf8/0x180)
[<8068cc20>] (__mutex_lock_slowpath) from [<8068cde0>] (mutex_lock+0x40/0x58)
[<8068cda0>] (mutex_lock) from [<8047c440>] (regmap_lock_mutex+0x18/0x1c)
[<8047c428>] (regmap_lock_mutex) from [<8047fedc>] (regcache_drop_region+0x44/0x144)
[<8047fe98>] (regcache_drop_region) from [<8047f0a4>] (_regmap_raw_write+0x65c/0x7f0)
[<8047ea48>] (_regmap_raw_write) from [<8047f2b8>] (_regmap_bus_raw_write+0x80/0x98)
[<8047f238>] (_regmap_bus_raw_write) from [<8047dea4>] (_regmap_write+0x11c/0x16c)
[<8047dd88>] (_regmap_write) from [<8047dfa4>] (_regmap_update_bits+0xb0/0xd4)
[<8047def4>] (_regmap_update_bits) from [<8047f460>] (regmap_update_bits_base+0x60/0x84)
[<8047f400>] (regmap_update_bits_base) from [<805acecc>] (snd_soc_component_update_bits+0x40/0x5c)
[<805ace8c>] (snd_soc_component_update_bits) from [<805adec0>] (snd_soc_put_volsw+0x9c/0xf8)
[<805ade24>] (snd_soc_put_volsw) from [<8058b070>] (snd_ctl_ioctl+0x75c/0xbe8)
[<8058a914>] (snd_ctl_ioctl) from [<80209d04>] (vfs_ioctl+0x30/0x44)
[<80209cd4>] (vfs_ioctl) from [<8020a5ec>] (do_vfs_ioctl+0x7b0/0x884)
[<80209e3c>] (do_vfs_ioctl) from [<8020a704>] (SyS_ioctl+0x44/0x6c)
[<8020a6c0>] (SyS_ioctl) from [<80107900>] (ret_fast_syscall+0x0/0x3c)

Signed-off-by: Elaine Zhang <zhangqing-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
---
 drivers/base/regmap/regmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 369a4c3c933e..cf848a61e64b 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1498,7 +1498,7 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 
 		kfree(buf);
 	} else if (ret != 0 && !map->cache_bypass && map->format.parse_val) {
-		regcache_drop_region(map, reg, reg + 1);
+		map->cache_ops->drop(map, reg, reg + 1);
 	}
 
 	trace_regmap_hw_write_done(map, reg, val_len / map->format.val_bytes);
-- 
1.9.1

Re: [PATCH] regmap: fix up the regmap lock error

[Mark Brown]

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On Thu, Sep 22, 2016 at 06:17:45PM +0800, Elaine Zhang wrote:

> Regmap lock is taken in regmap_update_bits_base() and then
> regcache_drop_region() tries to take it again.
> which added in commit 815806e39bf6
> ("regmap: drop cache if the bus transfer error")

Someone already sent a change for this.

> Backtrace:
> [<8068ab7c>] (__schedule) from [<8068b1c4>] (schedule+0xb8/0xd0)
> [<8068b10c>] (schedule) from [<8068b61c>] (schedule_preempt_disabled+0x20/0x2c)

Please think hard before including complete backtraces in upstream
reports, they are very large and contain almost no useful information
relative to their size so often obscure the relevant content in your
message. If part of the backtrace is usefully illustrative then it's
usually better to pull out the relevant sections.

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