Hello,
My static tool DSAC reports many sleep-in-atomic-context bugs involving
regmap_lock_mutex(), so I wonder whether this function is possible to be
executed in atomic context.
Here are some example bugs and their call paths in Linux-4.16 (from
bottom to top, and [FUNC_PTR] means that there is a function pointer call):
[FUNC] mutex_lock_nested
drivers/base/regmap/regmap.c, 468:
mutex_lock_nested in regmap_lock_mutex
drivers/base/regmap/regmap.c, 2503:
[FUNC_PTR]regmap_lock_mutex in regmap_read
drivers/clk/clk-aspeed.c, 215:
regmap_read in aspeed_clk_is_enabled
drivers/clk/clk-aspeed.c, 230:
aspeed_clk_is_enabled in aspeed_clk_enable
drivers/clk/clk-aspeed.c, 228:
_raw_spin_lock_irqsave in aspeed_clk_enable
[FUNC] mutex_lock_nested
drivers/base/regmap/regmap.c, 468:
mutex_lock_nested in regmap_lock_mutex
drivers/base/regmap/regmap.c, 2821:
[FUNC_PTR]regmap_lock_mutex in regmap_update_bits_base
drivers/clk/clk-aspeed.c, 270:
regmap_update_bits_base in aspeed_clk_disable
drivers/clk/clk-aspeed.c, 267:
_raw_spin_lock_irqsave in aspeed_clk_disable
[FUNC] mutex_lock_nested
drivers/base/regmap/regmap.c, 468:
mutex_lock_nested in regmap_lock_mutex
drivers/base/regmap/regmap.c, 2503:
[FUNC_PTR]regmap_lock_mutex in regmap_read
drivers/char/ipmi/bt-bmc.c, 385:
regmap_read in bt_bmc_irq
[FUNC] mutex_lock_nested
drivers/base/regmap/regmap.c, 468:
mutex_lock_nested in regmap_lock_mutex
drivers/base/regmap/regmap.c, 2821:
[FUNC_PTR]regmap_lock_mutex in regmap_update_bits_base
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c, 213:
regmap_update_bits_base in hdmi_modb
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c, 429:
hdmi_modb in hdmi_set_cts_n
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c, 527:
hdmi_set_cts_n in hdmi_set_clk_regenerator
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c, 524:
spin_lock_irq in hdmi_set_clk_regenerator
[FUNC] mutex_lock_nested
drivers/base/regmap/regmap.c, 468:
mutex_lock_nested in regmap_lock_mutex
drivers/base/regmap/regmap.c, 2503:
[FUNC_PTR]regmap_lock_mutex in regmap_read
drivers/media/platform/atmel/atmel-isc.c, 1603:
regmap_read in isc_interrupt (interrupt handler)
I find the code about the assignment of regmap_lock_mutex():
if ((bus && bus->fast_io) ||
config->fast_io) {
spin_lock_init(&map->spinlock);
map->lock = regmap_lock_spinlock;
map->unlock = regmap_unlock_spinlock;
lockdep_set_class_and_name(&map->spinlock,
lock_key, lock_name);
} else {
mutex_init(&map->mutex);
map->lock = regmap_lock_mutex;
map->unlock = regmap_unlock_mutex;
lockdep_set_class_and_name(&map->mutex,
lock_key, lock_name);
}
But after reading the code, I cannot find the relationship between the
if condition and atomic context.
I am looking forward to your reply, thanks in advance :)
Best wishes,
Jia-Ju Bai