| Message ID | 20190122154407.18417-1-osalvador@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm,memory_hotplug: Fix scan_movable_pages for gigantic hugepages | expand |
On 1/22/19 7:44 AM, Oscar Salvador wrote: > This is the same sort of error we saw in [1]. > > Gigantic hugepages crosses several memblocks, so it can be > that the page we get in scan_movable_pages() is a page-tail > belonging to a 1G-hugepage. > If that happens, page_hstate()->size_to_hstate() will return NULL, > and we will blow up in hugepage_migration_supported(). > > The splat is as follows: > > kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > kernel: #PF error: [normal kernel read fault] > kernel: PGD 0 P4D 0 > kernel: Oops: 0000 [#1] SMP PTI > kernel: CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 > kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > kernel: Call Trace: > kernel: ? klist_next+0x79/0xe0 > kernel: memory_subsys_offline+0x42/0x60 > kernel: device_offline+0x80/0xa0 > kernel: state_store+0xab/0xc0 > kernel: kernfs_fop_write+0x102/0x180 > kernel: __vfs_write+0x26/0x190 > kernel: ? set_close_on_exec+0x49/0x70 > kernel: vfs_write+0xad/0x1b0 > kernel: ksys_write+0x42/0x90 > kernel: do_syscall_64+0x5b/0x180 > kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9 > kernel: RIP: 0033:0x7ff1719febe4 > kernel: Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a fc 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83 > kernel: RSP: 002b:00007ffd50b7ddc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > kernel: RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007ff1719febe4 > kernel: RDX: 0000000000000008 RSI: 00005556e9216b20 RDI: 0000000000000001 > kernel: RBP: 00005556e9216b20 R08: 000000000000000a R09: 0000000000000000 > kernel: R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000008 > kernel: R13: 0000000000000001 R14: 00007ff171cca720 R15: 0000000000000008 > kernel: Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) > kernel: CR2: 0000000000000008 > kernel: ---[ end trace bdb71590872849fb ]--- > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fix this by getting the head page and testing against it. > > [1] https://patchwork.kernel.org/patch/10739963/ > > Signed-off-by: Oscar Salvador <osalvador@suse.de> Looks good. Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com> > --- > mm/memory_hotplug.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index ec22c86d9f89..25aee4f04a72 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1335,12 +1335,17 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > if (__PageMovable(page)) > return pfn; > if (PageHuge(page)) { > - if (hugepage_migration_supported(page_hstate(page)) && > - page_huge_active(page)) > + struct page *head = compound_head(page); > + > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > return pfn; > - else > - pfn = round_up(pfn + 1, > - 1 << compound_order(page)) - 1; > + else { > + unsigned long skip; > + > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; > + } > } > } > }
On Tue 22-01-19 16:44:07, Oscar Salvador wrote: > This is the same sort of error we saw in [1]. > > Gigantic hugepages crosses several memblocks, so it can be > that the page we get in scan_movable_pages() is a page-tail > belonging to a 1G-hugepage. > If that happens, page_hstate()->size_to_hstate() will return NULL, > and we will blow up in hugepage_migration_supported(). > > The splat is as follows: > > kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > kernel: #PF error: [normal kernel read fault] > kernel: PGD 0 P4D 0 > kernel: Oops: 0000 [#1] SMP PTI > kernel: CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 > kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > kernel: Call Trace: > kernel: ? klist_next+0x79/0xe0 > kernel: memory_subsys_offline+0x42/0x60 > kernel: device_offline+0x80/0xa0 > kernel: state_store+0xab/0xc0 > kernel: kernfs_fop_write+0x102/0x180 > kernel: __vfs_write+0x26/0x190 > kernel: ? set_close_on_exec+0x49/0x70 > kernel: vfs_write+0xad/0x1b0 > kernel: ksys_write+0x42/0x90 > kernel: do_syscall_64+0x5b/0x180 > kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9 > kernel: RIP: 0033:0x7ff1719febe4 > kernel: Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a fc 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83 > kernel: RSP: 002b:00007ffd50b7ddc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > kernel: RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007ff1719febe4 > kernel: RDX: 0000000000000008 RSI: 00005556e9216b20 RDI: 0000000000000001 > kernel: RBP: 00005556e9216b20 R08: 000000000000000a R09: 0000000000000000 > kernel: R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000008 > kernel: R13: 0000000000000001 R14: 00007ff171cca720 R15: 0000000000000008 > kernel: Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) > kernel: CR2: 0000000000000008 > kernel: ---[ end trace bdb71590872849fb ]--- > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fix this by getting the head page and testing against it. > > [1] https://patchwork.kernel.org/patch/10739963/ So this should be probably folded into the above patch as it is incomplete unless I am missing something. > Signed-off-by: Oscar Salvador <osalvador@suse.de> Other than that the change looks good to me. Acked-by: Michal Hocko <mhocko@suse.com> > --- > mm/memory_hotplug.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index ec22c86d9f89..25aee4f04a72 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1335,12 +1335,17 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > if (__PageMovable(page)) > return pfn; > if (PageHuge(page)) { > - if (hugepage_migration_supported(page_hstate(page)) && > - page_huge_active(page)) > + struct page *head = compound_head(page); > + > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > return pfn; > - else > - pfn = round_up(pfn + 1, > - 1 << compound_order(page)) - 1; > + else { > + unsigned long skip; > + > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; > + } > } > } > } > -- > 2.13.7
On Wed, Jan 23, 2019 at 10:47:17AM +0100, Michal Hocko wrote: > So this should be probably folded into the above patch as it is > incomplete unless I am missing something. Well, they are triggered from different paths. The former error was triggered in: removable_show is_mem_section_removable is_pageblock_removable_nolock has_unmovable_pages while this one is triggered when actually doing the offline operation __offline_pages scan_movable_pages But I do agree that one without the other is not really useful, an incomplete. The truth is that I did not spot this one when fixing [1] because I did not really try to offline the memblock back then, so my fault. While I agree that the best approach would be to fold this one into [1], I am not sure if it is too late for that as it seems that [1] was already released into mainline, and moreover to stable. I guess I will have Andrew decide what is the best way to carry on here. [1] https://patchwork.kernel.org/patch/10739963/ > > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > > Other than that the change looks good to me. > > Acked-by: Michal Hocko <mhocko@suse.com> Thanks!
On Wed 23-01-19 11:18:42, Oscar Salvador wrote: > On Wed, Jan 23, 2019 at 10:47:17AM +0100, Michal Hocko wrote: > > So this should be probably folded into the above patch as it is > > incomplete unless I am missing something. > > Well, they are triggered from different paths. > The former error was triggered in: > > removable_show > is_mem_section_removable > is_pageblock_removable_nolock > has_unmovable_pages > > while this one is triggered when actually doing the offline operation But it would trigger from the offline path as well, no? > __offline_pages > scan_movable_pages > > But I do agree that one without the other is not really useful, an incomplete. > The truth is that I did not spot this one when fixing [1] because I did not > really try to offline the memblock back then, so my fault. I should have noticed that during the review but those paths are really far away from each other so this is hard to spot indeed > While I agree that the best approach would be to fold this one into [1], > I am not sure if it is too late for that as it seems that [1] was already > released into mainline, and moreover to stable. OK, I wasn't aware of that. Then my suggestion is clearly moot. > I guess I will have Andrew decide what is the best way to carry on here. > > [1] https://patchwork.kernel.org/patch/10739963/ > > > > > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > > > > Other than that the change looks good to me. > > > > Acked-by: Michal Hocko <mhocko@suse.com> > > Thanks! > -- > Oscar Salvador > SUSE L3
On 22.01.19 16:44, Oscar Salvador wrote: > This is the same sort of error we saw in [1]. > > Gigantic hugepages crosses several memblocks, so it can be > that the page we get in scan_movable_pages() is a page-tail > belonging to a 1G-hugepage. > If that happens, page_hstate()->size_to_hstate() will return NULL, > and we will blow up in hugepage_migration_supported(). > > The splat is as follows: > > kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > kernel: #PF error: [normal kernel read fault] > kernel: PGD 0 P4D 0 > kernel: Oops: 0000 [#1] SMP PTI > kernel: CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 > kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > kernel: Call Trace: > kernel: ? klist_next+0x79/0xe0 > kernel: memory_subsys_offline+0x42/0x60 > kernel: device_offline+0x80/0xa0 > kernel: state_store+0xab/0xc0 > kernel: kernfs_fop_write+0x102/0x180 > kernel: __vfs_write+0x26/0x190 > kernel: ? set_close_on_exec+0x49/0x70 > kernel: vfs_write+0xad/0x1b0 > kernel: ksys_write+0x42/0x90 > kernel: do_syscall_64+0x5b/0x180 > kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9 > kernel: RIP: 0033:0x7ff1719febe4 > kernel: Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a fc 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83 > kernel: RSP: 002b:00007ffd50b7ddc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > kernel: RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007ff1719febe4 > kernel: RDX: 0000000000000008 RSI: 00005556e9216b20 RDI: 0000000000000001 > kernel: RBP: 00005556e9216b20 R08: 000000000000000a R09: 0000000000000000 > kernel: R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000008 > kernel: R13: 0000000000000001 R14: 00007ff171cca720 R15: 0000000000000008 > kernel: Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) > kernel: CR2: 0000000000000008 > kernel: ---[ end trace bdb71590872849fb ]--- > kernel: RIP: 0010:__offline_pages+0x6ae/0x900 > kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 > kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 > kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 > kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 > kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 > kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 > kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 > kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 > kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 > kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fix this by getting the head page and testing against it. > > [1] https://patchwork.kernel.org/patch/10739963/ > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > --- > mm/memory_hotplug.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index ec22c86d9f89..25aee4f04a72 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1335,12 +1335,17 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > if (__PageMovable(page)) > return pfn; > if (PageHuge(page)) { > - if (hugepage_migration_supported(page_hstate(page)) && > - page_huge_active(page)) > + struct page *head = compound_head(page); > + > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > return pfn; > - else > - pfn = round_up(pfn + 1, > - 1 << compound_order(page)) - 1; > + else { If you use {} for the else case, please also do so for the if case. Apart from that this looks good to me Reviewed-by: David Hildenbrand <david@redhat.com> > + unsigned long skip; > + > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; > + } > } > } > } >
On Wed, Jan 23, 2019 at 11:33:56AM +0100, David Hildenbrand wrote: > If you use {} for the else case, please also do so for the if case. Diff on top: diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 25aee4f04a72..d5810e522b72 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1338,9 +1338,9 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) struct page *head = compound_head(page); if (hugepage_migration_supported(page_hstate(head)) && - page_huge_active(head)) + page_huge_active(head)) { return pfn; - else { + } else { unsigned long skip; skip = (1 << compound_order(head)) - (page - head); > Apart from that this looks good to me > > Reviewed-by: David Hildenbrand <david@redhat.com> Thanks David ;-)
On Tue, 22 Jan 2019 16:44:07 +0100 Oscar Salvador <osalvador@suse.de> wrote: > This is the same sort of error we saw in [1]. I'll replace "[1]" with 17e2e7d7e1b83 ("mm, page_alloc: fix has_unmovable_pages for HugePages"). > Signed-off-by: Oscar Salvador <osalvador@suse.de> And I'll add cc:stable.
On Fri, 25 Jan 2019 08:58:33 +0100 Oscar Salvador <osalvador@suse.de> wrote: > On Wed, Jan 23, 2019 at 11:33:56AM +0100, David Hildenbrand wrote: > > If you use {} for the else case, please also do so for the if case. > > Diff on top: > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 25aee4f04a72..d5810e522b72 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1338,9 +1338,9 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > struct page *head = compound_head(page); > > if (hugepage_migration_supported(page_hstate(head)) && > - page_huge_active(head)) > + page_huge_active(head)) { > return pfn; > - else { > + } else { > unsigned long skip; > > skip = (1 << compound_order(head)) - (page - head); > The indenting is getting a bit deep also, so how about this? static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { unsigned long pfn; for (pfn = start; pfn < end; pfn++) { struct page *page, *head; if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); if (PageLRU(page)) return pfn; if (__PageMovable(page)) return pfn; if (!PageHuge(page)) continue; head = compound_head(page); if (hugepage_migration_supported(page_hstate(head)) && page_huge_active(head)) { return pfn; } else { unsigned long skip; skip = (1 << compound_order(head)) - (page - head); pfn += skip - 1; } } return 0; } From: Andrew Morton <akpm@linux-foundation.org> Subject: mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix fix brace layout, per David. Also reduce indentation Cc: Anthony Yznaga <anthony.yznaga@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/memory_hotplug.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix +++ a/mm/memory_hotplug.c @@ -1305,27 +1305,29 @@ int test_pages_in_a_zone(unsigned long s static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { unsigned long pfn; - struct page *page; + for (pfn = start; pfn < end; pfn++) { - if (pfn_valid(pfn)) { - page = pfn_to_page(pfn); - if (PageLRU(page)) - return pfn; - if (__PageMovable(page)) - return pfn; - if (PageHuge(page)) { - struct page *head = compound_head(page); + struct page *page, *head; + + if (!pfn_valid(pfn)) + continue; + page = pfn_to_page(pfn); + if (PageLRU(page)) + return pfn; + if (__PageMovable(page)) + return pfn; - if (hugepage_migration_supported(page_hstate(head)) && - page_huge_active(head)) - return pfn; - else { - unsigned long skip; + if (!PageHuge(page)) + continue; + head = compound_head(page); + if (hugepage_migration_supported(page_hstate(head)) && + page_huge_active(head)) { + return pfn; + } else { + unsigned long skip; - skip = (1 << compound_order(head)) - (page - head); - pfn += skip - 1; - } - } + skip = (1 << compound_order(head)) - (page - head); + pfn += skip - 1; } } return 0;
On Mon, 28 Jan 2019 14:53:09 -0800 Andrew Morton <akpm@linux-foundation.org> wrote: > On Fri, 25 Jan 2019 08:58:33 +0100 Oscar Salvador <osalvador@suse.de> wrote: > > > On Wed, Jan 23, 2019 at 11:33:56AM +0100, David Hildenbrand wrote: > > > If you use {} for the else case, please also do so for the if case. > > > > Diff on top: > > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > > index 25aee4f04a72..d5810e522b72 100644 > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > @@ -1338,9 +1338,9 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > > struct page *head = compound_head(page); > > > > if (hugepage_migration_supported(page_hstate(head)) && > > - page_huge_active(head)) > > + page_huge_active(head)) { > > return pfn; > > - else { > > + } else { > > unsigned long skip; > > > > skip = (1 << compound_order(head)) - (page - head); > > > > The indenting is getting a bit deep also, so how about this? > > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > > for (pfn = start; pfn < end; pfn++) { > struct page *page, *head; > > if (!pfn_valid(pfn)) > continue; > page = pfn_to_page(pfn); > if (PageLRU(page)) > return pfn; > if (__PageMovable(page)) > return pfn; > > if (!PageHuge(page)) > continue; > head = compound_head(page); > if (hugepage_migration_supported(page_hstate(head)) && > page_huge_active(head)) { > return pfn; checkpatch pointed out that else-after-return isn't needed so we can do static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { unsigned long pfn; for (pfn = start; pfn < end; pfn++) { struct page *page, *head; unsigned long skip; if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); if (PageLRU(page)) return pfn; if (__PageMovable(page)) return pfn; if (!PageHuge(page)) continue; head = compound_head(page); if (hugepage_migration_supported(page_hstate(head)) && page_huge_active(head)) return pfn; skip = (1 << compound_order(head)) - (page - head); pfn += skip - 1; } return 0; } --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix +++ a/mm/memory_hotplug.c @@ -1305,28 +1305,27 @@ int test_pages_in_a_zone(unsigned long s static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { unsigned long pfn; - struct page *page; + for (pfn = start; pfn < end; pfn++) { - if (pfn_valid(pfn)) { - page = pfn_to_page(pfn); - if (PageLRU(page)) - return pfn; - if (__PageMovable(page)) - return pfn; - if (PageHuge(page)) { - struct page *head = compound_head(page); + struct page *page, *head; + unsigned long skip; - if (hugepage_migration_supported(page_hstate(head)) && - page_huge_active(head)) - return pfn; - else { - unsigned long skip; + if (!pfn_valid(pfn)) + continue; + page = pfn_to_page(pfn); + if (PageLRU(page)) + return pfn; + if (__PageMovable(page)) + return pfn; - skip = (1 << compound_order(head)) - (page - head); - pfn += skip - 1; - } - } - } + if (!PageHuge(page)) + continue; + head = compound_head(page); + if (hugepage_migration_supported(page_hstate(head)) && + page_huge_active(head)) + return pfn; + skip = (1 << compound_order(head)) - (page - head); + pfn += skip - 1; } return 0; }
On Mon 28-01-19 14:56:17, Andrew Morton wrote: [...] > --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix > +++ a/mm/memory_hotplug.c > @@ -1305,28 +1305,27 @@ int test_pages_in_a_zone(unsigned long s > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > - struct page *page; > + > for (pfn = start; pfn < end; pfn++) { > - if (pfn_valid(pfn)) { > - page = pfn_to_page(pfn); > - if (PageLRU(page)) > - return pfn; > - if (__PageMovable(page)) > - return pfn; > - if (PageHuge(page)) { > - struct page *head = compound_head(page); > + struct page *page, *head; > + unsigned long skip; > > - if (hugepage_migration_supported(page_hstate(head)) && > - page_huge_active(head)) > - return pfn; > - else { > - unsigned long skip; > + if (!pfn_valid(pfn)) > + continue; > + page = pfn_to_page(pfn); > + if (PageLRU(page)) > + return pfn; > + if (__PageMovable(page)) > + return pfn; > > - skip = (1 << compound_order(head)) - (page - head); > - pfn += skip - 1; > - } > - } > - } > + if (!PageHuge(page)) > + continue; > + head = compound_head(page); > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > + return pfn; > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; > } > return 0; > } > _ > LGTM
On Mon, Jan 28, 2019 at 02:56:17PM -0800, Andrew Morton wrote: > > --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix > +++ a/mm/memory_hotplug.c > @@ -1305,28 +1305,27 @@ int test_pages_in_a_zone(unsigned long s > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > - struct page *page; > + > for (pfn = start; pfn < end; pfn++) { > - if (pfn_valid(pfn)) { > - page = pfn_to_page(pfn); > - if (PageLRU(page)) > - return pfn; > - if (__PageMovable(page)) > - return pfn; > - if (PageHuge(page)) { > - struct page *head = compound_head(page); > + struct page *page, *head; > + unsigned long skip; > > - if (hugepage_migration_supported(page_hstate(head)) && > - page_huge_active(head)) > - return pfn; > - else { > - unsigned long skip; > + if (!pfn_valid(pfn)) > + continue; > + page = pfn_to_page(pfn); > + if (PageLRU(page)) > + return pfn; > + if (__PageMovable(page)) > + return pfn; > > - skip = (1 << compound_order(head)) - (page - head); > - pfn += skip - 1; > - } > - } > - } > + if (!PageHuge(page)) > + continue; > + head = compound_head(page); > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > + return pfn; > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; > } > return 0; > } It looks much better, thanks a lot for the cleanup Andrew!
On 28.01.19 23:56, Andrew Morton wrote: > On Mon, 28 Jan 2019 14:53:09 -0800 Andrew Morton <akpm@linux-foundation.org> wrote: > >> On Fri, 25 Jan 2019 08:58:33 +0100 Oscar Salvador <osalvador@suse.de> wrote: >> >>> On Wed, Jan 23, 2019 at 11:33:56AM +0100, David Hildenbrand wrote: >>>> If you use {} for the else case, please also do so for the if case. >>> >>> Diff on top: >>> >>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >>> index 25aee4f04a72..d5810e522b72 100644 >>> --- a/mm/memory_hotplug.c >>> +++ b/mm/memory_hotplug.c >>> @@ -1338,9 +1338,9 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) >>> struct page *head = compound_head(page); >>> >>> if (hugepage_migration_supported(page_hstate(head)) && >>> - page_huge_active(head)) >>> + page_huge_active(head)) { >>> return pfn; >>> - else { >>> + } else { >>> unsigned long skip; >>> >>> skip = (1 << compound_order(head)) - (page - head); >>> >> >> The indenting is getting a bit deep also, so how about this? >> >> static unsigned long scan_movable_pages(unsigned long start, unsigned long end) >> { >> unsigned long pfn; >> >> for (pfn = start; pfn < end; pfn++) { >> struct page *page, *head; >> >> if (!pfn_valid(pfn)) >> continue; >> page = pfn_to_page(pfn); >> if (PageLRU(page)) >> return pfn; >> if (__PageMovable(page)) >> return pfn; >> >> if (!PageHuge(page)) >> continue; >> head = compound_head(page); >> if (hugepage_migration_supported(page_hstate(head)) && >> page_huge_active(head)) { >> return pfn; > > checkpatch pointed out that else-after-return isn't needed so we can do > > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > > for (pfn = start; pfn < end; pfn++) { > struct page *page, *head; > unsigned long skip; > > if (!pfn_valid(pfn)) > continue; > page = pfn_to_page(pfn); > if (PageLRU(page)) > return pfn; > if (__PageMovable(page)) > return pfn; > > if (!PageHuge(page)) > continue; > head = compound_head(page); > if (hugepage_migration_supported(page_hstate(head)) && > page_huge_active(head)) > return pfn; > skip = (1 << compound_order(head)) - (page - head); > pfn += skip - 1; > } > return 0; > } > > --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix > +++ a/mm/memory_hotplug.c > @@ -1305,28 +1305,27 @@ int test_pages_in_a_zone(unsigned long s > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > - struct page *page; > + > for (pfn = start; pfn < end; pfn++) { > - if (pfn_valid(pfn)) { > - page = pfn_to_page(pfn); > - if (PageLRU(page)) > - return pfn; > - if (__PageMovable(page)) > - return pfn; > - if (PageHuge(page)) { > - struct page *head = compound_head(page); > + struct page *page, *head; > + unsigned long skip; > > - if (hugepage_migration_supported(page_hstate(head)) && > - page_huge_active(head)) > - return pfn; > - else { > - unsigned long skip; > + if (!pfn_valid(pfn)) > + continue; > + page = pfn_to_page(pfn); > + if (PageLRU(page)) > + return pfn; > + if (__PageMovable(page)) > + return pfn; > > - skip = (1 << compound_order(head)) - (page - head); > - pfn += skip - 1; > - } > - } > - } > + if (!PageHuge(page)) > + continue; > + head = compound_head(page); > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > + return pfn; > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; Not sure if encoding the -1 in the previous line is even better now that we have more space skip = (1 << compound_order(head)) - (page - head + 1); Looks good to me. > } > return 0; > } > _ >
On Tue, Jan 29, 2019 at 11:03:56AM +0100, David Hildenbrand wrote: > Not sure if encoding the -1 in the previous line is even better now that > we have more space > > skip = (1 << compound_order(head)) - (page - head + 1); > > Looks good to me. > > > } I would rather not do that. For me looks a bit "subtle" why do we add up 1 after substracting page - head. I think that doing "skip - 1" looks more clear, but I do not have a strong opinion here.
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index ec22c86d9f89..25aee4f04a72 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1335,12 +1335,17 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) if (__PageMovable(page)) return pfn; if (PageHuge(page)) { - if (hugepage_migration_supported(page_hstate(page)) && - page_huge_active(page)) + struct page *head = compound_head(page); + + if (hugepage_migration_supported(page_hstate(head)) && + page_huge_active(head)) return pfn; - else - pfn = round_up(pfn + 1, - 1 << compound_order(page)) - 1; + else { + unsigned long skip; + + skip = (1 << compound_order(head)) - (page - head); + pfn += skip - 1; + } } } }
This is the same sort of error we saw in [1]. Gigantic hugepages crosses several memblocks, so it can be that the page we get in scan_movable_pages() is a page-tail belonging to a 1G-hugepage. If that happens, page_hstate()->size_to_hstate() will return NULL, and we will blow up in hugepage_migration_supported(). The splat is as follows: kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 kernel: #PF error: [normal kernel read fault] kernel: PGD 0 P4D 0 kernel: Oops: 0000 [#1] SMP PTI kernel: CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 kernel: RIP: 0010:__offline_pages+0x6ae/0x900 kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 kernel: Call Trace: kernel: ? klist_next+0x79/0xe0 kernel: memory_subsys_offline+0x42/0x60 kernel: device_offline+0x80/0xa0 kernel: state_store+0xab/0xc0 kernel: kernfs_fop_write+0x102/0x180 kernel: __vfs_write+0x26/0x190 kernel: ? set_close_on_exec+0x49/0x70 kernel: vfs_write+0xad/0x1b0 kernel: ksys_write+0x42/0x90 kernel: do_syscall_64+0x5b/0x180 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9 kernel: RIP: 0033:0x7ff1719febe4 kernel: Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a fc 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83 kernel: RSP: 002b:00007ffd50b7ddc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 kernel: RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007ff1719febe4 kernel: RDX: 0000000000000008 RSI: 00005556e9216b20 RDI: 0000000000000001 kernel: RBP: 00005556e9216b20 R08: 000000000000000a R09: 0000000000000000 kernel: R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000008 kernel: R13: 0000000000000001 R14: 00007ff171cca720 R15: 0000000000000008 kernel: Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) kernel: CR2: 0000000000000008 kernel: ---[ end trace bdb71590872849fb ]--- kernel: RIP: 0010:__offline_pages+0x6ae/0x900 kernel: Code: 48 c7 c6 d0 3e a4 81 e8 44 c8 ad ff 49 8b 04 24 bf 00 10 00 00 a9 00 00 01 00 74 09 41 0f b6 4c 24 51 48 d3 e7 e8 42 2a c1 ff <8b> 40 08 83 f8 09 0f 84 b0 fc ff ff 83 f8 12 0f 84 a7 fc ff ff 83 kernel: RSP: 0018:ffffc900008e3d20 EFLAGS: 00010246 kernel: RAX: 0000000000000000 RBX: ffffea0000000000 RCX: 0000000000000009 kernel: RDX: ffffffff825c64f0 RSI: 0000000000001000 RDI: 0000000000001000 kernel: RBP: ffffc900008e3d68 R08: 0000000000200000 R09: 00000000000001e4 kernel: R10: 0000000000000058 R11: ffffffff8254a854 R12: ffffea0004200000 kernel: R13: 0000000000108000 R14: 0000000000110000 R15: 0000000000000000 kernel: FS: 00007ff172339b80(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 0000000000000008 CR3: 0000000038d78006 CR4: 00000000003606a0 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fix this by getting the head page and testing against it. [1] https://patchwork.kernel.org/patch/10739963/ Signed-off-by: Oscar Salvador <osalvador@suse.de> --- mm/memory_hotplug.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)