> On Mar 8, 2020, at 7:14 PM, Rafael Aquini <aquini@xxxxxxxxxx> wrote: > > On Sat, Mar 07, 2020 at 10:20:20PM -0500, Qian Cai wrote: >> Not sure if it is really worth hurrying this into -rc5 now given... >> >>> On Mar 6, 2020, at 10:05 PM, Rafael Aquini <aquini@xxxxxxxxxx> wrote: >>>> >>>> After reverted this patch, it is no longer possible to reproduce a bug under memory pressure >>>> with swapping on linux-next 20200306, >>>> >>> >>> Would you mind sharing your .config ? Also it would be nice to know your >>> system and workload details so I can try to reproduce. >> >> LTP oom02 in a tight loop, >> >> # i=0; while :; echo $((i++)); ./oom02; sleep 10; done >> >> HPE ProLiant DL385 Gen10 >> AMD EPYC 7601 32-Core Processor >> 65536 MB memory, 400 GB disk space >> >> Processors 128 >> Cores 64 >> Sockets 2 >> >> linux-next 20200306 >> > > Thx! what about your .config? https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config My theory is this race, >From 73d4e8dad6cb248970bade5049cc072cd9090d0f Mon Sep 17 00:00:00 2001 From: Qian Cai <cai@xxxxxx> Date: Sun, 8 Mar 2020 17:37:51 -0400 Subject: [PATCH] mm/mprotect: fix a race in change_pmd_range() The recent commit increased the race window between, CPU0: task_numa_work() change_prot_numa() change_protection() change_protection_range() change_pmd_range() pmd_none_or_clear_bad_unless_trans_huge(pmd) <-- PMD is NULL. goto next; CPU1: do_huge_pmd_anonymous_page() __do_huge_pmd_anonymous_page() PMD is transhuge. where it will not calling __split_huge_pmd() properly and trigger a crash later on, kernel BUG at include/linux/page-flags.h:317! end_swap_bio_write() SetPageError(page) VM_BUG_ON_PAGE(1 && PageCompound(page)) Fix it by using a similar check in pmd_trans_unstable(). Fixes: 8b272b3cbbb5 ("mm, numa: fix bad pmd by atomically check for pmd_trans_huge when marking page tables prot_numa") Signed-off-by: Qian Cai <cai@xxxxxx> --- mm/mprotect.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 311c0dadf71c..00dd2c66a434 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -165,7 +165,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, * Used when setting automatic NUMA hinting protection where it is * critical that a numa hinting PMD is not confused with a bad PMD. */ -static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) +static inline int pmd_clear_bad_unless_none_or_trans_huge(pmd_t *pmd) { pmd_t pmdval = pmd_read_atomic(pmd); @@ -174,9 +174,7 @@ static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) barrier(); #endif - if (pmd_none(pmdval)) - return 1; - if (pmd_trans_huge(pmdval)) + if (pmd_none(pmdval) || pmd_trans_huge(pmdval)) return 0; if (unlikely(pmd_bad(pmdval))) { pmd_clear_bad(pmd); @@ -213,7 +211,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, * for all the checks. */ if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) && - pmd_none_or_clear_bad_unless_trans_huge(pmd)) + pmd_clear_bad_unless_none_or_trans_huge(pmd)) goto next; /* invoke the mmu notifier if the pmd is populated */ -- 2.21.0 (Apple Git-122.2) > > > > Cheers, > -- Rafael > >>>> The trace is a bit off for some reasons, but it is basically, >>>> >>>> kernel BUG at include/linux/page-flags.h:317! >>>> >>>> end_swap_bio_write() >>>> SetPageError(page) >>>> VM_BUG_ON_PAGE(1 && PageCompound(page)) >>>> >>>> The page was allocated in, >>>> >>>> do_huge_pmd_anonymous_page() >>>> >>>> [ 9598.551238][ T794] oom_reaper: reaped process 49120 (oom02), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB >>>> [ 9690.896638][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc0000 flags=0x0010] >>>> [ 9690.910129][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc1000 flags=0x0010] >>>> [ 9690.923933][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc1900 flags=0x0010] >>>> [ 9690.937669][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc1d00 flags=0x0010] >>>> [ 9690.951468][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc2000 flags=0x0010] >>>> [ 9690.964803][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc2400 flags=0x0010] >>>> [ 9690.978256][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc2800 flags=0x0010] >>>> [ 9690.991423][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc2c00 flags=0x0010] >>>> [ 9691.004294][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc3000 flags=0x0010] >>>> [ 9691.017228][ T814] smartpqi 0000:23:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0027 address=0xffffffffffcc3400 flags=0x0010] >>>> [ 9691.029804][ T814] AMD-Vi: Event logged [IO_PAGE_FAULT device=23:00.0 domain=0x0027 address=0xffffffffffcc3800 flags=0x0010] >>>> [ 9691.041623][ T814] AMD-Vi: Event logged [IO_PAGE_FAULT device=23:00.0 domain=0x0027 address=0xffffffffffcc3c00 flags=0x0010] >>>> [ 9692.767064][ C8] smartpqi 0000:23:00.0: controller is offline: status code 0x14803 >>>> [ 9692.775562][ C8] smartpqi 0000:23:00.0: controller offline >>>> [ 9692.841721][ C36] sd 0:1:0:0: [sda] tag#693 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.841970][ C87] blk_update_request: I/O error, dev sda, sector 59046400 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.842718][ C31] blk_update_request: I/O error, dev sda, sector 36509696 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.842748][ C18] sd 0:1:0:0: [sda] tag#616 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.842757][ C28] sd 0:1:0:0: [sda] tag#841 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.842766][ C109] sd 0:1:0:0: [sda] tag#393 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.842811][ C109] sd 0:1:0:0: [sda] tag#393 CDB: opcode=0x2a 2a 00 01 60 c8 00 00 02 00 00 >>>> [ 9692.842840][ C13] sd 0:1:0:0: [sda] tag#324 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.842924][ C18] sd 0:1:0:0: [sda] tag#616 CDB: opcode=0x2a 2a 00 01 c7 8c 00 00 02 00 00 >>>> [ 9692.842932][ C109] blk_update_request: I/O error, dev sda, sector 23119872 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.842938][ C28] sd 0:1:0:0: [sda] tag#841 CDB: opcode=0x2a 2a 00 03 2f cc 00 00 02 00 00 >>>> [ 9692.842984][ T213] sd 0:1:0:0: [sda] tag#47 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.842995][ C28] blk_update_request: I/O error, dev sda, sector 53464064 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843000][ C81] sd 0:1:0:0: [sda] tag#10 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.843031][ C18] blk_update_request: I/O error, dev sda, sector 29854720 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843056][ C13] sd 0:1:0:0: [sda] tag#324 CDB: opcode=0x2a 2a 00 03 17 66 00 00 02 00 00 >>>> [ 9692.843101][ C81] sd 0:1:0:0: [sda] tag#10 CDB: opcode=0x2a 2a 00 00 52 a4 00 00 02 00 00 >>>> [ 9692.843129][ C13] blk_update_request: I/O error, dev sda, sector 51865088 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843192][ C81] blk_update_request: I/O error, dev sda, sector 5415936 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843338][ T213] sd 0:1:0:0: [sda] tag#47 CDB: opcode=0x2a 2a 00 02 be 5a 00 00 02 00 00 >>>> [ 9692.843358][ C13] sd 0:1:0:0: [sda] tag#325 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.843480][ T213] blk_update_request: I/O error, dev sda, sector 46029312 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843485][ C13] sd 0:1:0:0: [sda] tag#325 CDB: opcode=0x2a 2a 00 03 17 68 00 00 02 00 00 >>>> [ 9692.843510][ C13] blk_update_request: I/O error, dev sda, sector 51865600 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843685][ C103] blk_update_request: I/O error, dev sda, sector 34941952 op 0x1:(WRITE) flags 0x8004000 phys_seg 4 prio class 0 >>>> [ 9692.843725][ C96] sd 0:1:0:0: [sda] tag#877 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.843744][ C92] Write-error on swap-device (254:1:39256632) >>>> [ 9692.843791][ C118] sd 0:1:0:0: [sda] tag#230 UNKNOWN(0x2003) Result: hostbyte=0x01 driverbyte=0x00 cmd_age=1s >>>> [ 9692.843866][ C64] Write-error on swap-device (254:1:63030016) >>>> [ 9692.843891][ C96] sd 0:1:0:0: [sda] tag#877 CDB: opcode=0x2a 2a 00 03 1e 48 00 00 02 00 00 >>>> [ 9692.844013][ C118] sd 0:1:0:0: [sda] tag#230 CDB: opcode=0x2a 2a 00 03 c6 26 00 00 02 00 00 >>>> [ 9692.844615][ C92] Write-error on swap-device (254:1:39256640) >>>> [ 9692.844643][ C64] Write-error on swap-device (254:1:63030024) >>>> [ 9692.845109][ C61] Write-error on swap-device (254:1:17105384) >>>> [ 9692.845192][ C25] page:fffff3b2ec3a8000 refcount:512 mapcount:0 mapping:000000009eb0338c index:0x7f6e58200 head:fffff3b2ec3a8000 order:9 compound_mapcount:0 compound_pincount:0 >>>> [ 9692.845226][ C25] anon flags: 0x45fffe0000d8454(uptodate|lru|workingset|owner_priv_1|writeback|head|reclaim|swapbacked) >>>> [ 9692.845254][ C25] raw: 045fffe0000d8454 fffff3b2f9d48008 fffff3b2f3270008 ffff97c3090f8209 >>>> [ 9692.845283][ C25] raw: 00000007f6e58200 000000000053c800 00000200ffffffff ffff97c8d71e9000 >>>> [ 9692.845293][ C122] Write-error on swap-device (254:1:39080184) >>>> [ 9692.845316][ T213] page:fffff3b2f77d8000 refcount:512 mapcount:0 mapping:00000000a4517f4e index:0x7f69d2200 head:fffff3b2f77d8000 order:9 compound_mapcount:0 compound_pincount:0 >>>> [ 9692.845330][ C25] page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page)) >>>> [ 9692.845427][ T213] anon flags: 0x45fffe0000d8454(uptodate|lru|workingset|owner_priv_1|writeback|head|reclaim|swapbacked) >>>> [ 9692.845433][ C25] page->mem_cgroup:ffff97c8d71e9000 >>>> [ 9692.845443][ C25] page_owner tracks the page as allocated >>>> [ 9692.845520][ T213] raw: 045fffe0000d8454 fffff3b2f5ec2f08 fffff3b2f6b88008 ffff97c715cc0609 >>>> [ 9692.845535][ C25] page last allocated via order 9, migratetype Movable, gfp_mask 0x1c20ca(GFP_TRANSHUGE_LIGHT) >>>> [ 9692.845606][ C25] prep_new_page+0x1cd/0x1f0 >>>> [ 9692.845628][ C25] get_page_from_freelist+0x18ac/0x24d0 >>>> [ 9692.845639][ T213] raw: 00000007f69d2200 00000000000bf400 00000200ffffffff ffff97c8d71e9000 >>>> [ 9692.845654][ C25] __alloc_pages_nodemask+0x1b1/0x450 >>>> [ 9692.845733][ T213] page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page)) >>>> [ 9692.845757][ C25] alloc_pages_vma+0x8a/0x2c0 >>>> [ 9692.845762][ T213] page->mem_cgroup:ffff97c8d71e9000 >>>> [ 9692.845779][ C25] do_huge_pmd_anonymous_page+0x1d4/0xc30 >>>> [ 9692.845786][ T213] page_owner tracks the page as allocated >>>> [ 9692.845807][ C25] __handle_mm_fault+0xd27/0xd50 >>>> [ 9692.845819][ T213] page last allocated via order 9, migratetype Movable, gfp_mask 0x1c20ca(GFP_TRANSHUGE_LIGHT) >>>> [ 9692.845833][ C25] handle_mm_fault+0xfc/0x2f0 >>>> [ 9692.845856][ T213] prep_new_page+0x1cd/0x1f0 >>>> [ 9692.845876][ C25] do_page_fault+0x263/0x6f9 >>>> [ 9692.845892][ T213] get_page_from_free7219][ C25] clone_endio+0xe4/0x2c0 [dm_mod] >>>> [ 9692.847226][ T213] kernel BUG at include/linux/page-flags.h:317! >>>> [ 9692.847234][ C64] Write-error on swap-device (254:1:63030064) >>>> [ 9692.847250][ C25] bio_endio+0x297/0x560 >>>> [ 9692.847255][ C61] Write-error on swap-device (254:1:17105424) >>>> [ 9692.847263][ C25] ? bio_advance+0x92/0x190 >>>> [ 9692.847267][ C122] Write-error on swap-device (254:1:39080224) >>>> [ 9692.847276][ C25] blk_update_request+0x201/0x920 >>>> [ 9692.847287][ C25] ? ___ratelimit+0x138/0x1e0 >>>> [ 9692.847312][ C25] scsi_end_request+0x6b/0x4b0 >>>> [ 9692.847320][ C25] ? ___ratelimit+0x3e/0x1e0 >>>> [ 9692.847329][ C25] scsi_io_completion+0x509/0x7e0 >>>> [ 9692.847340][ C25] scsi_finish_command+0x1ed/0x2a0 >>>> [ 9692.847350][ C25] scsi_softirq_done+0x1c9/0x1d0 >>>> [ 9692.847354][ C64] Write-error on swap-device (254:1:63030072) >>>> [ 9692.847363][ C25] ? blk_mq_check_inflight+0xa0/0xa0 >>>> [ 9692.847383][ C61] Write-error on swap-device (254:1:17105432) >>>> [ 9692.847397][ C122] Write-erro692.848242][ C25] RSP: 0018:ffffb02006b68bb0 EFLAGS: 00010086 >>>> [ 9692.848333][ T213] Workqueue: events pqi_ctrl_offline_worker [smartpqi] >>>> [ 9692.848346][ C61] Write-error on swap-device (254:1:17105528) >>>> [ 9692.848351][ C122] Write-error on swap-device (254:1:39080328) >>>> [ 9692.848428][ C25] RAX: 0000000000000000 RBX: ffff97c76d8d4b80 RCX: ffffffff9d51e8f0 >>>> [ 9692.848433][ C61] Write-error on swap-device (254:1:17105536) >>>> [ 9692.848437][ C122] Write-error on swap-device (254:1:39080336) >>>> [ 9692.848445][ T213] RIP: 0010:end_swap_bio_write+0x90/0x280 >>>> [ 9692.848450][ C25] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff97c7e539f00a >>>> [ 9692.848461][ T213] Code: 80 7b 1a 00 0f 84 58 01 00 00 4c 89 e6 bf 10 00 00 00 e8 33 f8 ff ff 84 c0 74 1d 48 c7 c6 18 7e 3b 9a 4c 89 e7 e8 20 78 fa ff <0f> 0b 48 c7 c7 b0 0b 6e 9a e8 04 ee 2b 00 4d 8d 74 24 08 ba 08 00 >>>> [ 9692.848466][ C25] RBP: ffffb02006b68bf0 R08: 0000000000000000 R09: 000097c7e539f00a >>>> [ 9692.848471][ T213] RSP: 0018:ffffb02006dd3908 EFLAGS: 00010286 >>>> [ 9692.848485][ C25] R10: 0000b02006b689a0 R11: 000097c7e5ax_pmem_core efivars acpi_cpufreq efivarfs ip_tables x_tables xfs sd_mod smartpqi scsi_transport_sas tg3 mlx5_core >>>> [ 9692.849818][ C122] Write-error on swap-device (254:1:39080440) >>>> [ 9692.849884][ T213] libphy >>>> [ 9692.849889][ C122] Write-error on swap-device (254:1:39080448) >>>> [ 9692.849952][ T213] firmware_class >>>> [ 9692.849959][ C122] Write-error on swap-device (254:1:39080456) >>>> [ 9692.849963][ T213] dm_mirror dm_region_hash dm_log dm_mod >>>> [ 9692.849990][ C122] Write-error on swap-device (254:1:39080464) >>>> [ 9692.850069][ C122] Write-error on swap-device (254:1:39080472) >>>> [ 9692.850107][ C122] Write-error on swap-device (254:1:39080480) >>>> [ 9692.850156][ C122] Write-error on swap-device (254:1:39080488) >>>> [ 9692.850220][ C122] Write-error on swap-device (254:1:39080496) >>>> [ 9692.850264][ C122] Write-error on swap-device (254:1:39080504) >>>> [ 9692.850323][ C122] Write-error on swap-device (254:1:39080512) >>>> [ 9692.850361][ C122] Write-error on swap-device (254:1:39080520) >>>> [ 9692.850411][ C122] Write-error on swap-device (254:1:39080528) >>>> >>>>> >>>>> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> >>>>> Cc: stable@xxxxxxxxxxxxxxx >>>>> Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx> >>>>> --- >>>>> mm/mprotect.c | 38 ++++++++++++++++++++++++++++++++++++-- >>>>> 1 file changed, 36 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/mm/mprotect.c b/mm/mprotect.c >>>>> index 7a8e84f86831..9ea8cc0ab2fd 100644 >>>>> --- a/mm/mprotect.c >>>>> +++ b/mm/mprotect.c >>>>> @@ -161,6 +161,31 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, >>>>> return pages; >>>>> } >>>>> >>>>> +/* >>>>> + * Used when setting automatic NUMA hinting protection where it is >>>>> + * critical that a numa hinting PMD is not confused with a bad PMD. >>>>> + */ >>>>> +static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) >>>>> +{ >>>>> + pmd_t pmdval = pmd_read_atomic(pmd); >>>>> + >>>>> + /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */ >>>>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE >>>>> + barrier(); >>>>> +#endif >>>>> + >>>>> + if (pmd_none(pmdval)) >>>>> + return 1; >>>>> + if (pmd_trans_huge(pmdval)) >>>>> + return 0; >>>>> + if (unlikely(pmd_bad(pmdval))) { >>>>> + pmd_clear_bad(pmd); >>>>> + return 1; >>>>> + } >>>>> + >>>>> + return 0; >>>>> +} >>>>> + >>>>> static inline unsigned long change_pmd_range(struct vm_area_struct *vma, >>>>> pud_t *pud, unsigned long addr, unsigned long end, >>>>> pgprot_t newprot, int dirty_accountable, int prot_numa) >>>>> @@ -178,8 +203,17 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, >>>>> unsigned long this_pages; >>>>> >>>>> next = pmd_addr_end(addr, end); >>>>> - if (!is_swap_pmd(*pmd) && !pmd_trans_huge(*pmd) && !pmd_devmap(*pmd) >>>>> - && pmd_none_or_clear_bad(pmd)) >>>>> + >>>>> + /* >>>>> + * Automatic NUMA balancing walks the tables with mmap_sem >>>>> + * held for read. It's possible a parallel update to occur >>>>> + * between pmd_trans_huge() and a pmd_none_or_clear_bad() >>>>> + * check leading to a false positive and clearing. >>>>> + * Hence, it's ecessary to atomically read the PMD value >>>>> + * for all the checks. >>>>> + */ >>>>> + if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) && >>>>> + pmd_none_or_clear_bad_unless_trans_huge(pmd)) >>>>> goto next; >>>>> >>>>> /* invoke the mmu notifier if the pmd is populated */ >>>>> -- >>>>> 2.24.1
