On Fri, 2007-08-03 at 17:20 +0530, Pradyumna Sampath wrote: > Hi, > I am running linux-2.6.22.1-rt8 on mpc5200 and on running stress > > #./stress --cpu 8 --io 4 --vm 2 --vm-bytes 2M --timeout 300s > > I get the following stack.But this does not happen with non -rt kernel. > > LR = 0xff51fcc > BUG: scheduling while atomic: stress/0x00000002/739, CPU#0 > Call Trace: > [c04fbb80] [c0008650] show_stack+0x50/0x190 (unreliable) > [c04fbbb0] [c0016fc0] __schedule_bug+0x38/0x48 > [c04fbbc0] [c01d4f7c] __schedule+0x3dc/0x450 > [c04fbbf0] [c01d56c8] schedule+0x54/0xf0 > [c04fbc00] [c01d6390] rt_spin_lock_slowlock+0x100/0x224 > [c04fbc60] [c0052198] get_zone_pcp+0x30/0x58 > [c04fbc80] [c0053078] free_hot_cold_page+0x114/0x1fc > [c04fbcb0] [c0056424] put_page+0x50/0x15c > [c04fbcd0] [c0069854] free_page_and_swap_cache+0x44/0x80 > [c04fbce0] [c005d760] unmap_vmas+0x2e0/0x788 > [c04fbd70] [c006292c] exit_mmap+0x74/0x108 > [c04fbda0] [c001adc0] mmput+0x54/0xf0 > [c04fbdc0] [c001ecfc] exit_mm+0xc0/0x124 > [c04fbde0] [c001ffd0] do_exit+0x164/0x8bc > [c04fbe20] [c0020760] do_group_exit+0x38/0x90 > [c04fbe40] [c002ba48] get_signal_to_deliver+0x2ac/0x3c0 > [c04fbe70] [c000739c] do_signal+0x50/0x60c > [c04fbf40] [c000fec0] do_user_signal+0x74/0xc4 > --- Exception: c00 at 0xfeab1dc > LR = 0xff51fcc > > I have also tested the same case on x86 and that does not throw up > anything. Another observation is the fact is that this happens when > --vm is > 1. So I am guessing its a very PowerPC specific problem. > Maybe some part of the vm code for powerpc. This happens for all > powerpc -rt kernels I have used.
Weird. unmap_vmas calls to free_page_and_swap_cache() should be happening within a get/put_cpu section, thus with preempt disabled, thus I fail to see how rt_spin_lock would be allowed to preempt. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
