| Message ID | 20240216073340.55404-1-byungchul@sk.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] sched/numa, mm: do not promote folios to nodes not set N_MEMORY | expand |
On 16.02.24 08:33, Byungchul Park wrote: > Changes from v1: > 1. Trim the verbose oops in the commit message. (feedbacked by > Phil Auld) > 2. Rewrite a comment in code. (feedbacked by Phil Auld) > > --->8--- > From 6830b59db267a31b78f6f09af12ae0e3132b4bca Mon Sep 17 00:00:00 2001 > From: Byungchul Park <byungchul@sk.com> > Date: Fri, 16 Feb 2024 16:26:23 +0900 > Subject: [PATCH v2] sched/numa, mm: do not promote folios to nodes not set N_MEMORY > > While running qemu with a configuration where some CPUs don't have their > local memory and with a kernel numa balancing on, the following oops has > been observed. It's because of null pointers of ->zone_pgdat of zones of > those nodes that are not initialized properly at booting time. So should > avoid nodes not set N_MEMORY from getting promoted. > >> BUG: unable to handle page fault for address: 00000000000033f3 >> #PF: supervisor read access in kernel mode >> #PF: error_code(0x0000) - not-present page >> PGD 0 P4D 0 >> Oops: 0000 [#1] PREEMPT SMP NOPTI >> CPU: 2 PID: 895 Comm: masim Not tainted 6.6.0-dirty #255 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS >> rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 >> RIP: 0010:wakeup_kswapd (./linux/mm/vmscan.c:7812) >> Code: (omitted) >> RSP: 0000:ffffc90004257d58 EFLAGS: 00010286 >> RAX: ffffffffffffffff RBX: ffff88883fff0480 RCX: 0000000000000003 >> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88883fff0480 >> RBP: ffffffffffffffff R08: ff0003ffffffffff R09: ffffffffffffffff >> R10: ffff888106c95540 R11: 0000000055555554 R12: 0000000000000003 >> R13: 0000000000000000 R14: 0000000000000000 R15: ffff88883fff0940 >> FS: 00007fc4b8124740(0000) GS:ffff888827c00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00000000000033f3 CR3: 000000026cc08004 CR4: 0000000000770ee0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> PKRU: 55555554 >> Call Trace: >> <TASK> >> ? __die >> ? page_fault_oops >> ? __pte_offset_map_lock >> ? exc_page_fault >> ? asm_exc_page_fault >> ? wakeup_kswapd >> migrate_misplaced_page >> __handle_mm_fault >> handle_mm_fault >> do_user_addr_fault >> exc_page_fault >> asm_exc_page_fault >> RIP: 0033:0x55b897ba0808 >> Code: (omitted) >> RSP: 002b:00007ffeefa821a0 EFLAGS: 00010287 >> RAX: 000055b89983acd0 RBX: 00007ffeefa823f8 RCX: 000055b89983acd0 >> RDX: 00007fc2f8122010 RSI: 0000000000020000 RDI: 000055b89983acd0 >> RBP: 00007ffeefa821a0 R08: 0000000000000037 R09: 0000000000000075 >> R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 >> R13: 00007ffeefa82410 R14: 000055b897ba5dd8 R15: 00007fc4b8340000 >> </TASK> > This sounds like we need a Fixes: and want to CC stable?
On Fri, Feb 16, 2024 at 10:07:53AM +0100, David Hildenbrand wrote: > On 16.02.24 08:33, Byungchul Park wrote: > > Changes from v1: > > 1. Trim the verbose oops in the commit message. (feedbacked by > > Phil Auld) > > 2. Rewrite a comment in code. (feedbacked by Phil Auld) > > > > --->8--- > > From 6830b59db267a31b78f6f09af12ae0e3132b4bca Mon Sep 17 00:00:00 2001 > > From: Byungchul Park <byungchul@sk.com> > > Date: Fri, 16 Feb 2024 16:26:23 +0900 > > Subject: [PATCH v2] sched/numa, mm: do not promote folios to nodes not set N_MEMORY > > > > While running qemu with a configuration where some CPUs don't have their > > local memory and with a kernel numa balancing on, the following oops has > > been observed. It's because of null pointers of ->zone_pgdat of zones of > > those nodes that are not initialized properly at booting time. So should > > avoid nodes not set N_MEMORY from getting promoted. > > > > > BUG: unable to handle page fault for address: 00000000000033f3 > > > #PF: supervisor read access in kernel mode > > > #PF: error_code(0x0000) - not-present page > > > PGD 0 P4D 0 > > > Oops: 0000 [#1] PREEMPT SMP NOPTI > > > CPU: 2 PID: 895 Comm: masim Not tainted 6.6.0-dirty #255 > > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > > rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 > > > RIP: 0010:wakeup_kswapd (./linux/mm/vmscan.c:7812) > > > Code: (omitted) > > > RSP: 0000:ffffc90004257d58 EFLAGS: 00010286 > > > RAX: ffffffffffffffff RBX: ffff88883fff0480 RCX: 0000000000000003 > > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88883fff0480 > > > RBP: ffffffffffffffff R08: ff0003ffffffffff R09: ffffffffffffffff > > > R10: ffff888106c95540 R11: 0000000055555554 R12: 0000000000000003 > > > R13: 0000000000000000 R14: 0000000000000000 R15: ffff88883fff0940 > > > FS: 00007fc4b8124740(0000) GS:ffff888827c00000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00000000000033f3 CR3: 000000026cc08004 CR4: 0000000000770ee0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > PKRU: 55555554 > > > Call Trace: > > > <TASK> > > > ? __die > > > ? page_fault_oops > > > ? __pte_offset_map_lock > > > ? exc_page_fault > > > ? asm_exc_page_fault > > > ? wakeup_kswapd > > > migrate_misplaced_page > > > __handle_mm_fault > > > handle_mm_fault > > > do_user_addr_fault > > > exc_page_fault > > > asm_exc_page_fault > > > RIP: 0033:0x55b897ba0808 > > > Code: (omitted) > > > RSP: 002b:00007ffeefa821a0 EFLAGS: 00010287 > > > RAX: 000055b89983acd0 RBX: 00007ffeefa823f8 RCX: 000055b89983acd0 > > > RDX: 00007fc2f8122010 RSI: 0000000000020000 RDI: 000055b89983acd0 > > > RBP: 00007ffeefa821a0 R08: 0000000000000037 R09: 0000000000000075 > > > R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 > > > R13: 00007ffeefa82410 R14: 000055b897ba5dd8 R15: 00007fc4b8340000 > > > </TASK> > > > > This sounds like we need a Fixes: and want to CC stable? Sure. I will CC stable at the next spin - might need to rewrite the reason. Byungchul > -- > Cheers, > > David / dhildenb
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d7a3c63a2171..859ef78ef72b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1828,6 +1828,15 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, int dst_nid = cpu_to_node(dst_cpu); int last_cpupid, this_cpupid; + /* + * A node of dst_nid might not have its local memory. Promoting + * a folio to the node is meaningless. What's even worse, oops + * can be observed by the null pointer of ->zone_pgdat in + * various points of the code during migration. + */ + if (!node_state(dst_nid, N_MEMORY)) + return false; + /* * The pages in slow memory node should be migrated according * to hot/cold instead of private/shared.