LED heartbeat trigger - in_atomic() while allocs

Benedict, Michael MBenedict at twacs.com
Tue Nov 27 07:07:05 EST 2007


I was playing around with the LED heartbeat trigger and it caught the
BUG() code when trying to activate.  Does anyone know why this call
stack would be in_atomic()?  Or any ideas for a patch that would allow
the heartbeat trigger to allocate when it is not in atomic context?

BUG: sleeping function called from invalid context at mm/slab.c:3024
in_atomic():1, irqs_disabled():0
Call Trace:
[def3dd90] [c0008e60] show_stack+0x48/0x194 (unreliable)
[def3ddc0] [c0014160] __might_sleep+0xd0/0xdc
[def3dde0] [c0063e60] kmem_cache_zalloc+0xdc/0x12c
[def3de00] [c01975c0] heartbeat_trig_activate+0x24/0x80
[def3de20] [c0196844] led_trigger_set+0x128/0x160
[def3de40] [c0196988] led_trigger_store+0x10c/0x1a8
[def3deb0] [c0162f40] class_device_attr_store+0x44/0x5c
[def3dec0] [c00ae614] sysfs_write_file+0x114/0x1dc
[def3def0] [c0068ea4] vfs_write+0x9c/0x110
[def3df10] [c0068ff4] sys_write+0x4c/0x90
[def3df40] [c000fc00] ret_from_syscall+0x0/0x38
--- Exception: c01 at 0xfe83818
    LR = 0xfe35448

Kernel 2.6.22-4, powerpc, targeting an MPC 8347.  I don't think this
issue is PowerPC specific but I was hoping other embedded people might
have experience with the LED class driver.

Thank you,
	Michael



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