Hi Baolin, no memory hotplug. This happens usually during bootup when I've a WAN-link established. BR, Markus On 06/05/2024 11.39, Baolin Wang wrote: > [You don't often get email from baolin.wang@xxxxxxxxxxxxxxxxx. Learn > why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > Ccing David. > > On 2024/5/3 00:02, Markus Gothe wrote: >> Hi, >> under some rare occasion I run into the following crash: >> >> [ 41.417606] pstate: 80400005 (Nzcv daif +PAN -UAO) >> [ 41.422406] pc : set_pfnblock_flags_mask+0x50/0x94 >> [ 41.427193] lr : compaction_alloc+0x220/0x804 >> [ 41.431544] sp : ffffffc01104bb10 >> [ 41.434852] x29: ffffffc01104bb10 x28: ffffffc010e5b500 >> [ 41.440165] x27: 0000000000098000 x26: ffffffc010e5b500 >> [ 41.445477] x25: 0000000000000066 x24: 0000000000090800 >> [ 41.450789] x23: 0000000000000200 x22: 0000000000084000 >> [ 41.456093] x21: ffffffc010e82000 x20: ffffffc010b88000 >> [ 41.461396] x19: ffffffc01104bd70 x18: 0000000000000000 >> [ 41.466700] x17: f1f24e35df34dda4 x16: 6b3f63a0e1157268 >> [ 41.472004] x15: 4b3990ec2568ada0 x14: 757ebc126939cb5f >> [ 41.477308] x13: 9df9488aba179ccb x12: 0000000000000000 >> [ 41.482612] x11: 0000000000000000 x10: ffffffc010c5fc30 >> [ 41.487916] x9 : ffffff801eea7c00 x8 : 000000001bf00000 >> [ 41.493219] x7 : 0000000000000000 x6 : 000000000000003f >> [ 41.498525] x5 : 0000000000000108 x4 : 1000000000000000 >> [ 41.503835] x3 : 0000000000000021 x2 : 000000000000003c >> [ 41.509139] x1 : 0000000000000001 x0 : 0000000000000003 >> [ 41.514443] Call trace: >> [ 41.516887] set_pfnblock_flags_mask+0x50/0x94 >> [ 41.521330] migrate_pages+0x90/0x7f0 >> [ 41.524992] compact_zone+0x854/0x9f0 >> [ 41.528647] kcompactd_do_work+0x168/0x230 >> [ 41.532734] kcompactd+0x58/0x140 >> [ 41.536043] kthread+0x120/0x124 >> [ 41.539263] ret_from_fork+0x10/0x24 >> [ 41.542835] Code: d346fc43 4b0000c2 8b030ce5 9ac22084 (f86378e0) >> [ 41.548925] ---[ end trace 731400a587304db3 ]--- >> >> >> I've pin-pointed it down to pageblock_flags pointer being initialized >> to NULL under certain conditions. I don't know why this happens. >> Maybe it is some obscure race condition which only shows up on my >> system. > > Is there memory hotplug in your test? It seems to be caused by the race > between memory hotplug and PFN walkers (such as compaction), which is > already a known issue. > >> Nonetheless, I've made a fix for this in the attached patch. It adds >> sanity checking and protects the system for crashing. >> I think it is better to be safe than sorry. >> >> -- >> Best Regards, >> Markus >>
