Messages in this thread | | | From | Jia-Ju Bai <> | Subject | [BUG] Possible sleep-in-atomic-context bugs involving regmap_lock_mutex() | Date | Tue, 28 Aug 2018 16:57:51 +0800 |
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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
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