On Mon, Nov 10, 2025 at 01:22:16PM +0000, Lorenzo Stoakes wrote: > On Mon, Nov 10, 2025 at 06:37:58PM +0530, Garg, Shivank wrote: > > > > > > On 11/10/2025 5:31 PM, Lorenzo Stoakes wrote: > > > On Mon, Nov 10, 2025 at 11:32:53AM +0000, Shivank Garg wrote: > > >> When MADV_COLLAPSE is called on file-backed mappings (e.g., executable > > > > >> --- > > >> Applies cleanly on: > > >> 6.18-rc5 > > >> mm-stable:e9a6fb0bc > > > > > > Please base on mm-unstable. mm-stable is usually out of date until very > > > close to > > > merge window. > > > > I'm observing issues when testing with kselftest on mm-unstable and mm-new > > branches that prevent > > proper testing for my patches: > > > > On mm-unstable (without my patches): > > > > # # running ./transhuge-stress -d 20 > > # # -------------------------------- > > # # TAP version 13 > > # # 1..1 > > # # transhuge-stress: allocate 220271 transhuge pages, using 440543 MiB > > virtual memory and 1720 MiB of ram > > > > > > [ 367.225667] RIP: 0010:swap_cache_get_folio+0x2d/0xc0 > > [ 367.230635] Code: 00 00 48 89 f9 49 89 f9 48 89 fe 48 c1 e1 06 49 c1 e9 > > 3a 48 c1 e9 0f 48 c1 e1 05 4a 8b 04 cd c0 2e 5b 99 48 8b 78 60 48 01 cf > > <48> 8b 47 08 48 85 c0 74 20 48 89 f2 81 e2 ff 01 00 00 48 8d 04 d0 > > [ 367.249378] RSP: 0000:ffffcde32943fba8 EFLAGS: 00010282 > > [ 367.254605] RAX: ffff8bd1668fdc00 RBX: 00007ffc15df5000 RCX: > > 00003fffffffffe0 > > [ 367.261736] RDX: ffffffff995cb530 RSI: 0003ffffffffffff RDI: > > ffffcbd1560dffe0 > > [ 367.268862] RBP: 0003ffffffffffff R08: ffffcde32943fc47 R09: > > 0000000000000000 > > [ 367.275994] R10: 0000000000000000 R11: 0000000000000000 R12: > > 0000000000000000 > > [ 367.283129] R13: 0000000000000000 R14: ffff8bd1668fdc00 R15: > > 0000000000100cca > > [ 367.290260] FS: 00007ff600af5b80(0000) GS:ffff8c4e9ec7e000(0000) > > knlGS:0000000000000000 > > [ 367.298344] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 367.304083] CR2: ffffcbd1560dffe8 CR3: 00000001280e9001 CR4: > > 0000000000770ef0 > > [ 367.311216] PKRU: 55555554 > > [ 367.313929] Call Trace: > > [ 367.316375] <TASK> > > [ 367.318479] __read_swap_cache_async+0x8e/0x1b0 > > [ 367.323014] swap_vma_readahead+0x23d/0x430 > > [ 367.327198] swapin_readahead+0xb0/0xc0 > > [ 367.331039] do_swap_page+0x5bc/0x1260 > > [ 367.334789] ? rseq_ip_fixup+0x6f/0x190 > > [ 367.338631] ? __pfx_default_wake_function+0x10/0x10 > > [ 367.343596] __handle_mm_fault+0x49a/0x760 > > [ 367.347696] handle_mm_fault+0x188/0x300 > > [ 367.351620] do_user_addr_fault+0x15b/0x6c0 > > [ 367.355807] exc_page_fault+0x60/0x100 > > [ 367.359562] asm_exc_page_fault+0x22/0x30 > > [ 367.363574] RIP: 0033:0x7ff60091ba99 > > [ 367.367153] Code: f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 40 c4 01 00 f3 > > 0f 1e fa 80 3d b5 f5 0e 00 00 74 13 31 c0 0f 05 48 3d 00 f0 ff ff 77 4f > > <c3> 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec 20 48 89 55 e8 48 89 75 > > [ 367.385897] RSP: 002b:00007ffc15df1118 EFLAGS: 00010203 > > [ 367.391124] RAX: 0000000000000001 RBX: 000055941fb672a0 RCX: > > 00007ff60091ba91 > > [ 367.398256] RDX: 0000000000000001 RSI: 000055941fb813e0 RDI: > > 0000000000000000 > > [ 367.405387] RBP: 00007ffc15df21e0 R08: 0000000000000000 R09: > > 0000000000000007 > > [ 367.412513] R10: 000055941fb97cb0 R11: 0000000000000246 R12: > > 000055941fb813e0 > > [ 367.419646] R13: 0000000000000000 R14: 0000000000000000 R15: > > 0000000000000000 > > [ 367.426781] </TASK> > > [ 367.428970] Modules linked in: xfrm_user xfrm_algo xt_addrtype > > xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat > > nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables > > overlay bridge stp llc cfg80211 rfkill binfmt_misc ipmi_ssif amd_atl > > intel_rapl_msr intel_rapl_common wmi_bmof amd64_edac edac_mce_amd mgag200 > > rapl drm_client_lib i2c_algo_bit drm_shmem_helper drm_kms_helper > > acpi_cpufreq i2c_piix4 ptdma k10temp i2c_smbus wmi acpi_power_meter ipmi_si > > acpi_ipmi ipmi_devintf ipmi_msghandler sg dm_multipath drm fuse dm_mod > > nfnetlink ext4 crc16 mbcache jbd2 raid10 raid456 async_raid6_recov > > async_memcpy async_pq async_xor xor async_tx raid6_pq raid1 raid0 kvm_amd > > sd_mod ahci nvme libahci kvm libata nvme_core tg3 ccp megaraid_sas irqbypass > > [ 367.497528] CR2: ffffcbd1560dffe8 > > [ 367.500846] ---[ end trace 0000000000000000 ]--- > > Yikes, oopsies! > > I'll try running tests locally on threadripper, but ran tests against yours > previously and seemed fine, strange. Maybe fixed since but let me try, maybe > because swap is not enabled locally for me? > > Likely this actually...
I have tried on swap-enabled setup and no issue with mm-unstable. So this is odd, I know you have limited time (_totally sympathise_) but is it at all possible if you get a moment to bisect against tip mm-unstable/mm-new? Obviously we want to make sure buggy swap code doesn't get merged to mainline! > > > > > > > > > ----------------- > > On mm-new (without my patches): > > > > [ 394.144770] get_swap_device: Bad swap offset entry 3ffffffffffff > > > > dmesg | grep "get_swap_device: Bad swap offset entry" | wc -l > > 359 > > > > > > Additionally, kexec triggers an oops and crash during swapoff: > > > > > > Deactivating swap 704.854238] BUG: unable to handle page fault > > for address: ffffcbe2de8dffe8 > > [ 704.861524] #PF: supervisor read access in kernel mode > > ;39mswap.img.swa[ 704.866666] #PF: error_code(0x0000) - not-present page > > [ 704.873253] PGD 0 P4D 0 > > p - /swap.im[ 704.875790] Oops: Oops: 0000 [#1] SMP NOPTI > > g... > > [ 704.881354] CPU: 122 UID: 0 PID: 107680 Comm: swapoff Kdump: loaded Not > > tainted 6.18.0-rc5+ #11 NONE > > [ 704.891283] Hardware name: Dell Inc. PowerEdge R6525/024PW1, BIOS 2.16.2 > > 07/09/2024 > > [ 704.898930] RIP: 0010:swap_cache_get_folio+0x2d/0xc0 > > [ 704.903907] Code: 00 00 48 89 f9 49 89 f9 48 89 fe 48 c1 e1 06 49 c1 e9 > > 3a 48 c1 e9 0f 48 c1 e1 05 4a 8b 04 cd c0 2e 7b 95 48 8b 78 60 48 01 cf > > <48> 8b 47 08 48 85 c0 74 20 48 89 f2 81 e2 ff 01 00 00 48 8d 04 d0 > > [ 704.922720] RSP: 0018:ffffcf1227b1fc08 EFLAGS: 00010282 > > [ 704.928035] RAX: ffff8be2cefb3c00 RBX: 0000555c65a5c000 RCX: > > 00003fffffffffe0 > > [ 704.928036] RDX: 0003ffffffffffff RSI: 0003ffffffffffff RDI: > > ffffcbe2de8dffe0 > > [ 704.928037] RBP: 0000000000000000 R08: ffff8be2de8e0520 R09: > > 0000000000000000 > > Unmount[ 704.928038] R10: 000000000000ffff R11: ffffcf12236f4000 > > R12: ffff8be2d5b8d968 > > [ 704.928039] R13: 0003ffffffffffff R14: fffff3eec85eb000 R15: > > 0000555c65a51000 > > [ 704.928039] FS: 00007f41fcab3800(0000) GS:ffff8c602b6fe000(0000) > > knlGS:0000000000000000 > > [ 704.928040] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 704.928041] CR2: ffffcbe2de8dffe8 CR3: 00000074981af004 CR4: > > 0000000000770ef0 > > [ 704.928041] PKRU: 55555554 > > [ 704.928042] Call Trace: > > [ 704.928043] <TASK> > > [ 704.928044] unuse_pte_range+0x10b/0x290 > > [ 704.928047] unuse_pud_range.isra.0+0x149/0x190 > > [ 704.928048] unuse_vma+0x1a6/0x220 > > [ 704.928050] unuse_mm+0x9b/0x110 > > [ 704.928052] try_to_unuse+0xc5/0x260 > > [ 704.928053] __do_sys_swapoff+0x244/0x670 > > ing boo[ 705.016662] do_syscall_64+0x67/0xc50 > > [ 705.016667] ? do_user_addr_fault+0x15b/0x6c0 > > t.mount - /b[ 705.026100] ? exc_page_fault+0x60/0x100 > > [ 705.031498] ? irqentry_exit_to_user_mode+0x20/0xe0 > > oot... > > [ 705.036377] entry_SYSCALL_64_after_hwframe+0x76/0x7e > > [ 705.042200] RIP: 0033:0x7f41fc9271bb > > [ 705.045780] Code: 0f 1e fa 48 83 fe 01 48 8b 15 59 bc 0d 00 19 c0 83 e0 > > f0 83 c0 26 64 89 02 b8 ff ff ff ff c3 f3 0f 1e fa b8 a8 00 00 00 0f 05 > > <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2d bc 0d 00 f7 d8 64 89 01 48 > > [ 705.064807] RSP: 002b:00007ffd14b5b6e8 EFLAGS: 00000202 ORIG_RAX: > > 00000000000000a8 > > [ 705.064809] RAX: ffffffffffffffda RBX: 00007ffd14b5cf30 RCX: > > 00007f41fc9271bb > > [ 705.064810] RDX: 0000000000000001 RSI: 0000000000000c00 RDI: > > 000055d48f533a40 > > [ 705.064810] RBP: 00007ffd14b5b750 R08: 00007f41fca03b20 R09: > > 0000000000000000 > > [ 705.064811] R10: 0000000000000001 R11: 0000000000000202 R12: > > 0000000000000000 > > [ 705.064811] R13: 0000000000000000 R14: 000055d4584f1479 R15: > > 000055d4584f2b20 > > [ 705.064813] </TASK> > > [ 705.064814] Modules linked in: xfrm_user xfrm_algo xt_addrtype > > xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat > > nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables > > overlay bridge stp llc cfg80211 rfkill binfmt_misc ipmi_ssif amd_atl > > intel_rapl_msr intel_rapl_common wmi_bmof amd64_edac edac_mce_amd rapl > > mgag200 drm_client_lib i2c_algo_bit drm_shmem_helper drm_kms_helper > > acpi_cpufreq i2c_piix4 ptdma ipmi_si k10temp i2c_smbus acpi_power_meter wmi > > acpi_ipmi ipmi_msghandler sg dm_multipath fuse drm dm_mod nfnetlink ext4 > > crc16 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq > > async_xor xor async_tx raid6_pq raid1 raid0 sd_mod kvm_amd ahci libahci kvm > > nvme tg3 libata ccp irqbypass nvme_core megaraid_sas [last unloaded: > > ipmi_devintf] > > [ 705.180420] CR2: ffffcbe2de8dffe8 > > [ 705.183852] ---[ end trace 0000000000000000 ]--- > > > > > > I haven't had cycles to dig into this yet and been swamped with other > > things. > > Fully understand, I'm _very_ familiar with this situation :) > > I need more cores... ;) Oh it's nice to have more :) I am bankrupt now, but it's nice to have more ;) Cheers, Lorenzo
