lwn.git/mm, branch v6.10-rc4

Merge tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

2024-06-13T17:09:29+00:00

Pull memblock fixes from Mike Rapoport: "Fix validation of NUMA coverage. memblock_validate_numa_coverage() was checking for a unset node ID using NUMA_NO_NODE, but x86 used MAX_NUMNODES when no node ID was specified by buggy firmware. Update memblock to substitute MAX_NUMNODES with NUMA_NO_NODE in memblock_set_node() and use NUMA_NO_NODE in x86::numa_init()" * tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: x86/mm/numa: Use NUMA_NO_NODE when calling memblock_set_node() memblock: make memblock_set_node() also warn about use of MAX_NUMNODES

mm: fix xyz_noprof functions calling profiled functions

2024-06-06T02:19:26+00:00

Grepping /proc/allocinfo for "noprof" reveals several xyz_noprof functions, which means internally they are calling profiled functions. This should never happen as such calls move allocation charge from a higher level location where it should be accounted for into these lower level helpers. Fix this by replacing profiled function calls with noprof ones. Link: https://lkml.kernel.org/r/20240531205350.3973009-1-surenb@google.com Fixes: b951aaff5035 ("mm: enable page allocation tagging") Fixes: e26d8769da6d ("mempool: hook up to memory allocation profiling") Fixes: 88ae5fb755b0 ("mm: vmalloc: enable memory allocation profiling") Signed-off-by: Suren Baghdasaryan Cc: Kent Overstreet Reviewed-by: Kees Cook Acked-by: Vlastimil Babka Cc: Pasha Tatashin Signed-off-by: Andrew Morton

codetag: avoid race at alloc_slab_obj_exts

2024-06-06T02:19:26+00:00

When CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled, the following warning may be noticed: [ 48.299584] ------------[ cut here ]------------ [ 48.300092] alloc_tag was not set [ 48.300528] WARNING: CPU: 2 PID: 1361 at include/linux/alloc_tag.h:130 alloc_tagging_slab_free_hook+0x84/0xc7 [ 48.301305] Modules linked in: [ 48.301553] CPU: 2 PID: 1361 Comm: systemd-udevd Not tainted 6.10.0-rc1-00003-gac8755535862 #176 [ 48.302196] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 48.302752] RIP: 0010:alloc_tagging_slab_free_hook+0x84/0xc7 [ 48.303169] Code: 8d 1c c4 48 85 db 74 4d 48 83 3b 00 75 1e 80 3d 65 02 86 04 00 75 15 48 c7 c7 11 48 1d 85 c6 05 55 02 86 04 01 e8 64 44 a5 ff <0f> 0b 48 8b 03 48 85 c0 74 21 48 83 f8 01 74 14 48 8b 50 20 48 f7 [ 48.304411] RSP: 0018:ffff8880111b7d40 EFLAGS: 00010282 [ 48.304916] RAX: 0000000000000000 RBX: ffff88800fcc9008 RCX: 0000000000000000 [ 48.305455] RDX: 0000000080000000 RSI: ffff888014060000 RDI: ffffed1002236f97 [ 48.305979] RBP: 0000000000001100 R08: fffffbfff0aa73a1 R09: 0000000000000000 [ 48.306473] R10: ffffffff814515e5 R11: 0000000000000003 R12: ffff88800fcc9000 [ 48.306943] R13: ffff88800b2e5cc0 R14: ffff8880111b7d90 R15: 0000000000000000 [ 48.307529] FS: 00007faf5d1908c0(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 [ 48.308223] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.308710] CR2: 000058fb220c9118 CR3: 00000000110cc000 CR4: 0000000000750ef0 [ 48.309274] PKRU: 55555554 [ 48.309804] Call Trace: [ 48.310029] [ 48.310290] ? show_regs+0x84/0x8d [ 48.310722] ? alloc_tagging_slab_free_hook+0x84/0xc7 [ 48.311298] ? __warn+0x13b/0x2ff [ 48.311580] ? alloc_tagging_slab_free_hook+0x84/0xc7 [ 48.311987] ? report_bug+0x2ce/0x3ab [ 48.312292] ? handle_bug+0x8c/0x107 [ 48.312563] ? exc_invalid_op+0x34/0x6f [ 48.312842] ? asm_exc_invalid_op+0x1a/0x20 [ 48.313173] ? this_cpu_in_panic+0x1c/0x72 [ 48.313503] ? alloc_tagging_slab_free_hook+0x84/0xc7 [ 48.313880] ? putname+0x143/0x14e [ 48.314152] kmem_cache_free+0xe9/0x214 [ 48.314454] putname+0x143/0x14e [ 48.314712] do_unlinkat+0x413/0x45e [ 48.315001] ? __pfx_do_unlinkat+0x10/0x10 [ 48.315388] ? __check_object_size+0x4d7/0x525 [ 48.315744] ? __sanitizer_cov_trace_pc+0x20/0x4a [ 48.316167] ? __sanitizer_cov_trace_pc+0x20/0x4a [ 48.316757] ? getname_flags+0x4ed/0x500 [ 48.317261] __x64_sys_unlink+0x42/0x4a [ 48.317741] do_syscall_64+0xe2/0x149 [ 48.318171] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 48.318602] RIP: 0033:0x7faf5d8850ab [ 48.318891] Code: fd ff ff e8 27 dd 01 00 0f 1f 80 00 00 00 00 f3 0f 1e fa b8 5f 00 00 00 0f 05 c3 0f 1f 40 00 f3 0f 1e fa b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 41 2d 0e 00 f7 d8 [ 48.320649] RSP: 002b:00007ffc44982b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 [ 48.321182] RAX: ffffffffffffffda RBX: 00005ba344a44680 RCX: 00007faf5d8850ab [ 48.321667] RDX: 0000000000000000 RSI: 00005ba344a44430 RDI: 00007ffc44982b40 [ 48.322139] RBP: 00007ffc44982c00 R08: 0000000000000000 R09: 0000000000000007 [ 48.322598] R10: 00005ba344a44430 R11: 0000000000000246 R12: 0000000000000000 [ 48.323071] R13: 00007ffc44982b40 R14: 0000000000000000 R15: 0000000000000000 [ 48.323596] This is due to a race when two objects are allocated from the same slab, which did not have an obj_exts allocated for. In such a case, the two threads will notice the NULL obj_exts and after one assigns slab->obj_exts, the second one will happily do the exchange if it reads this new assigned value. In order to avoid that, verify that the read obj_exts does not point to an allocated obj_exts before doing the exchange. Link: https://lkml.kernel.org/r/20240527183007.1595037-1-cascardo@igalia.com Fixes: 09c46563ff6d ("codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark failed slab_ext allocations") Signed-off-by: Thadeu Lima de Souza Cascardo Acked-by: Vlastimil Babka Cc: Suren Baghdasaryan Cc: Christoph Lameter Cc: David Rientjes Cc: Gustavo A. R. Silva Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Kees Cook Cc: Pekka Enberg Cc: Roman Gushchin Cc: Thadeu Lima de Souza Cascardo Cc: Kent Overstreet Signed-off-by: Andrew Morton

mm/hugetlb: do not call vma_add_reservation upon ENOMEM

2024-06-06T02:19:26+00:00

sysbot reported a splat [1] on __unmap_hugepage_range(). This is because vma_needs_reservation() can return -ENOMEM if allocate_file_region_entries() fails to allocate the file_region struct for the reservation. Check for that and do not call vma_add_reservation() if that is the case, otherwise region_abort() and region_del() will see that we do not have any file_regions. If we detect that vma_needs_reservation() returned -ENOMEM, we clear the hugetlb_restore_reserve flag as if this reservation was still consumed, so free_huge_folio() will not increment the resv count. [1] https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa Link: https://lkml.kernel.org/r/20240528205323.20439-1-osalvador@suse.de Fixes: df7a6d1f6405 ("mm/hugetlb: restore the reservation if needed") Signed-off-by: Oscar Salvador Reported-and-tested-by: syzbot+d3fe2dc5ffe9380b714b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/ Cc: Breno Leitao Cc: Muchun Song Cc: Signed-off-by: Andrew Morton

mm/ksm: fix ksm_zero_pages accounting

2024-06-06T02:19:26+00:00

We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages. So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users. Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages. Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou Acked-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Ran Xiaokai Cc: Stefan Roesch Cc: xu xin Cc: Yang Yang Cc: Signed-off-by: Andrew Morton

mm/ksm: fix ksm_pages_scanned accounting

2024-06-06T02:19:25+00:00

Patch series "mm/ksm: fix some accounting problems", v3. We encountered some abnormal ksm_pages_scanned and ksm_zero_pages during some random tests. 1. ksm_pages_scanned unchanged even ksmd scanning has progress. 2. ksm_zero_pages maybe -1 in some rare cases. This patch (of 2): During testing, I found ksm_pages_scanned is unchanged although the scan_get_next_rmap_item() did return valid rmap_item that is not NULL. The reason is the scan_get_next_rmap_item() will return NULL after a full scan, so ksm_do_scan() just return without accounting of the ksm_pages_scanned. Fix it by just putting ksm_pages_scanned accounting in that loop, and it will be accounted more timely if that loop would last for a long time. Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-0-34bb358fdc13@linux.dev Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-1-34bb358fdc13@linux.dev Fixes: b348b5fe2b5f ("mm/ksm: add pages scanned metric") Signed-off-by: Chengming Zhou Acked-by: David Hildenbrand Reviewed-by: xu xin Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Ran Xiaokai Cc: Stefan Roesch Cc: Yang Yang Cc: Signed-off-by: Andrew Morton

kmsan: do not wipe out origin when doing partial unpoisoning

2024-06-06T02:19:25+00:00

As noticed by Brian, KMSAN should not be zeroing the origin when unpoisoning parts of a four-byte uninitialized value, e.g.: char a[4]; kmsan_unpoison_memory(a, 1); This led to false negatives, as certain poisoned values could receive zero origins, preventing those values from being reported. To fix the problem, check that kmsan_internal_set_shadow_origin() writes zero origins only to slots which have zero shadow. Link: https://lkml.kernel.org/r/20240528104807.738758-1-glider@google.com Fixes: f80be4571b19 ("kmsan: add KMSAN runtime core") Signed-off-by: Alexander Potapenko Reported-by: Brian Johannesmeyer Link: https://lore.kernel.org/lkml/20240524232804.1984355-1-bjohannesmeyer@gmail.com/T/ Reviewed-by: Marco Elver Tested-by: Brian Johannesmeyer Cc: Dmitry Vyukov Cc: Kees Cook Cc: Signed-off-by: Andrew Morton

vmalloc: check CONFIG_EXECMEM in is_vmalloc_or_module_addr()

2024-06-06T02:19:25+00:00

After commit 2c9e5d4a0082 ("bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of") CONFIG_BPF_JIT does not depend on CONFIG_MODULES any more and bpf jit also uses the [MODULES_VADDR, MODULES_END] memory region. But is_vmalloc_or_module_addr() still checks CONFIG_MODULES, which then returns false for a bpf jit memory region when CONFIG_MODULES is not defined. It leads to the following kernel BUG: [ 1.567023] ------------[ cut here ]------------ [ 1.567883] kernel BUG at mm/vmalloc.c:745! [ 1.568477] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 1.569367] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.9.0+ #448 [ 1.570247] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 [ 1.570786] RIP: 0010:vmalloc_to_page+0x48/0x1ec [ 1.570786] Code: 0f 00 00 e8 eb 1a 05 00 b8 37 00 00 00 48 ba fe ff ff ff ff 1f 00 00 4c 03 25 76 49 c6 02 48 c1 e0 28 48 01 e8 48 39 d0 76 02 <0f> 0b 4c 89 e7 e8 bf 1a 05 00 49 8b 04 24 48 a9 9f ff ff ff 0f 84 [ 1.570786] RSP: 0018:ffff888007787960 EFLAGS: 00010212 [ 1.570786] RAX: 000036ffa0000000 RBX: 0000000000000640 RCX: ffffffff8147e93c [ 1.570786] RDX: 00001ffffffffffe RSI: dffffc0000000000 RDI: ffffffff840e32c8 [ 1.570786] RBP: ffffffffa0000000 R08: 0000000000000000 R09: 0000000000000000 [ 1.570786] R10: ffff888007787a88 R11: ffffffff8475d8e7 R12: ffffffff83e80ff8 [ 1.570786] R13: 0000000000000640 R14: 0000000000000640 R15: 0000000000000640 [ 1.570786] FS: 0000000000000000(0000) GS:ffff88806cc00000(0000) knlGS:0000000000000000 [ 1.570786] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.570786] CR2: ffff888006a01000 CR3: 0000000003e80000 CR4: 0000000000350ef0 [ 1.570786] Call Trace: [ 1.570786] [ 1.570786] ? __die_body+0x1b/0x58 [ 1.570786] ? die+0x31/0x4b [ 1.570786] ? do_trap+0x9d/0x138 [ 1.570786] ? vmalloc_to_page+0x48/0x1ec [ 1.570786] ? do_error_trap+0xcd/0x102 [ 1.570786] ? vmalloc_to_page+0x48/0x1ec [ 1.570786] ? vmalloc_to_page+0x48/0x1ec [ 1.570786] ? handle_invalid_op+0x2f/0x38 [ 1.570786] ? vmalloc_to_page+0x48/0x1ec [ 1.570786] ? exc_invalid_op+0x2b/0x41 [ 1.570786] ? asm_exc_invalid_op+0x16/0x20 [ 1.570786] ? vmalloc_to_page+0x26/0x1ec [ 1.570786] ? vmalloc_to_page+0x48/0x1ec [ 1.570786] __text_poke+0xb6/0x458 [ 1.570786] ? __pfx_text_poke_memcpy+0x10/0x10 [ 1.570786] ? __pfx___mutex_lock+0x10/0x10 [ 1.570786] ? __pfx___text_poke+0x10/0x10 [ 1.570786] ? __pfx_get_random_u32+0x10/0x10 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] text_poke_copy_locked+0x70/0x84 [ 1.570786] text_poke_copy+0x32/0x4f [ 1.570786] bpf_arch_text_copy+0xf/0x27 [ 1.570786] bpf_jit_binary_pack_finalize+0x26/0x5a [ 1.570786] bpf_int_jit_compile+0x576/0x8ad [ 1.570786] ? __pfx_bpf_int_jit_compile+0x10/0x10 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] ? __kmalloc_node_track_caller+0x2b5/0x2e0 [ 1.570786] bpf_prog_select_runtime+0x7c/0x199 [ 1.570786] bpf_prepare_filter+0x1e9/0x25b [ 1.570786] ? __pfx_bpf_prepare_filter+0x10/0x10 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] ? _find_next_bit+0x29/0x7e [ 1.570786] bpf_prog_create+0xb8/0xe0 [ 1.570786] ptp_classifier_init+0x75/0xa1 [ 1.570786] ? __pfx_ptp_classifier_init+0x10/0x10 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] ? register_pernet_subsys+0x36/0x42 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] sock_init+0x99/0xa3 [ 1.570786] ? __pfx_sock_init+0x10/0x10 [ 1.570786] do_one_initcall+0x104/0x2c4 [ 1.570786] ? __pfx_do_one_initcall+0x10/0x10 [ 1.570786] ? parameq+0x25/0x2d [ 1.570786] ? rcu_is_watching+0x1c/0x3c [ 1.570786] ? trace_kmalloc+0x81/0xb2 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] ? __kmalloc+0x29c/0x2c7 [ 1.570786] ? srso_return_thunk+0x5/0x5f [ 1.570786] do_initcalls+0xf9/0x123 [ 1.570786] kernel_init_freeable+0x24f/0x289 [ 1.570786] ? __pfx_kernel_init+0x10/0x10 [ 1.570786] kernel_init+0x19/0x13a [ 1.570786] ret_from_fork+0x24/0x41 [ 1.570786] ? __pfx_kernel_init+0x10/0x10 [ 1.570786] ret_from_fork_asm+0x1a/0x30 [ 1.570786] [ 1.570819] ---[ end trace 0000000000000000 ]--- [ 1.571463] RIP: 0010:vmalloc_to_page+0x48/0x1ec [ 1.572111] Code: 0f 00 00 e8 eb 1a 05 00 b8 37 00 00 00 48 ba fe ff ff ff ff 1f 00 00 4c 03 25 76 49 c6 02 48 c1 e0 28 48 01 e8 48 39 d0 76 02 <0f> 0b 4c 89 e7 e8 bf 1a 05 00 49 8b 04 24 48 a9 9f ff ff ff 0f 84 [ 1.574632] RSP: 0018:ffff888007787960 EFLAGS: 00010212 [ 1.575129] RAX: 000036ffa0000000 RBX: 0000000000000640 RCX: ffffffff8147e93c [ 1.576097] RDX: 00001ffffffffffe RSI: dffffc0000000000 RDI: ffffffff840e32c8 [ 1.577084] RBP: ffffffffa0000000 R08: 0000000000000000 R09: 0000000000000000 [ 1.578077] R10: ffff888007787a88 R11: ffffffff8475d8e7 R12: ffffffff83e80ff8 [ 1.578810] R13: 0000000000000640 R14: 0000000000000640 R15: 0000000000000640 [ 1.579823] FS: 0000000000000000(0000) GS:ffff88806cc00000(0000) knlGS:0000000000000000 [ 1.580992] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.581869] CR2: ffff888006a01000 CR3: 0000000003e80000 CR4: 0000000000350ef0 [ 1.582800] Kernel panic - not syncing: Fatal exception [ 1.583765] ---[ end Kernel panic - not syncing: Fatal exception ]--- Fix this by checking CONFIG_EXECMEM instead. Link: https://lkml.kernel.org/r/20240528160838.102223-1-xiyou.wangcong@gmail.com Fixes: 2c9e5d4a0082 ("bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of") Signed-off-by: Cong Wang Acked-by: Mike Rapoport (IBM) Cc: Luis Chamberlain Cc: Daniel Borkmann Signed-off-by: Andrew Morton

mm: page_alloc: fix highatomic typing in multi-block buddies

2024-06-06T02:19:25+00:00

Christoph reports a page allocator splat triggered by xfstests: generic/176 214s ... [ 1204.507931] run fstests generic/176 at 2024-05-27 12:52:30 XFS (nvme0n1): Mounting V5 Filesystem cd936307-415f-48a3-b99d-a2d52ae1f273 XFS (nvme0n1): Ending clean mount XFS (nvme1n1): Mounting V5 Filesystem ab3ee1a4-af62-4934-9a6a-6c2fde321850 XFS (nvme1n1): Ending clean mount XFS (nvme1n1): Unmounting Filesystem ab3ee1a4-af62-4934-9a6a-6c2fde321850 XFS (nvme1n1): Mounting V5 Filesystem 7099b02d-9c58-4d1d-be1d-2cc472d12cd9 XFS (nvme1n1): Ending clean mount ------------[ cut here ]------------ page type is 3, passed migratetype is 1 (nr=512) WARNING: CPU: 0 PID: 509870 at mm/page_alloc.c:645 expand+0x1c5/0x1f0 Modules linked in: i2c_i801 crc32_pclmul i2c_smbus [last unloaded: scsi_debug] CPU: 0 PID: 509870 Comm: xfs_io Not tainted 6.10.0-rc1+ #2437 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:expand+0x1c5/0x1f0 Code: 05 16 70 bf 02 01 e8 ca fc ff ff 8b 54 24 34 44 89 e1 48 c7 c7 80 a2 28 83 48 89 c6 b8 01 00 3 RSP: 0018:ffffc90003b2b968 EFLAGS: 00010082 RAX: 0000000000000000 RBX: ffffffff83fa9480 RCX: 0000000000000000 RDX: 0000000000000005 RSI: 0000000000000027 RDI: 00000000ffffffff RBP: 00000000001f2600 R08: 00000000fffeffff R09: 0000000000000001 R10: 0000000000000000 R11: ffffffff83676200 R12: 0000000000000009 R13: 0000000000000200 R14: 0000000000000001 R15: ffffea0007c98000 FS: 00007f72ca3d5780(0000) GS:ffff8881f9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f72ca1fff38 CR3: 00000001aa0c6002 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? __warn+0x7b/0x120 ? expand+0x1c5/0x1f0 ? report_bug+0x191/0x1c0 ? handle_bug+0x3c/0x80 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? expand+0x1c5/0x1f0 ? expand+0x1c5/0x1f0 __rmqueue_pcplist+0x3a9/0x730 get_page_from_freelist+0x7a0/0xf00 __alloc_pages_noprof+0x153/0x2e0 __folio_alloc_noprof+0x10/0xa0 __filemap_get_folio+0x16b/0x370 iomap_write_begin+0x496/0x680 While trying to service a movable allocation (page type 1), the page allocator runs into a two-pageblock buddy on the movable freelist whose second block is typed as highatomic (page type 3). This inconsistency is caused by the highatomic reservation system operating on single pageblocks, while MAX_ORDER can be bigger than that - in this configuration, pageblock_order is 9 while MAX_PAGE_ORDER is 10. The test case is observed to make several adjacent order-3 requests with __GFP_DIRECT_RECLAIM cleared, which marks the surrounding block as highatomic. Upon freeing, the blocks merge into an order-10 buddy. When the highatomic pool is drained later on, this order-10 buddy gets moved back to the movable list, but only the first pageblock is marked movable again. A subsequent expand() of this buddy warns about the tail being of a different type. This is a long-standing bug that's surfaced by the recent block type warnings added to the allocator. The consequences seem mostly benign, it just results in odd behavior: the highatomic tail blocks are not properly drained, instead they end up on the movable list first, then go back to the highatomic list after an alloc-free cycle. To fix this, make the highatomic reservation code aware that allocations/buddies can be larger than a pageblock. While it's an old quirk, the recently added type consistency warnings seem to be the most prominent consequence of it. Set the Fixes: tag accordingly to highlight this backporting dependency. Link: https://lkml.kernel.org/r/20240530114203.GA1222079@cmpxchg.org Fixes: e0932b6c1f94 ("mm: page_alloc: consolidate free page accounting") Signed-off-by: Johannes Weiner Reported-by: Christoph Hellwig Reviewed-by: Zi Yan Tested-by: Christoph Hellwig Cc: Andy Shevchenko Cc: Baolin Wang Cc: Mel Gorman Cc: Vlastimil Babka Signed-off-by: Andrew Morton

memcg: remove the lockdep assert from __mod_objcg_mlstate()

2024-06-06T02:19:24+00:00

The assert was introduced in the commit cited below as an insurance that the semantic is the same after the local_irq_save() has been removed and the function has been made static. The original requirement to disable interrupt was due the modification of per-CPU counters which require interrupts to be disabled because the counter update operation is not atomic and some of the counters are updated from interrupt context. All callers of __mod_objcg_mlstate() acquire a lock (memcg_stock.stock_lock) which disables interrupts on !PREEMPT_RT and the lockdep assert is satisfied. On PREEMPT_RT the interrupts are not disabled and the assert triggers. The safety of the counter update is already ensured by VM_WARN_ON_IRQS_ENABLED() which is part of __mod_memcg_lruvec_state() and does not require yet another check. Remove the lockdep assert from __mod_objcg_mlstate(). Link: https://lkml.kernel.org/r/20240528141341.rz_rytN_@linutronix.de Fixes: 91882c1617c1 ("memcg: simple cleanup of stats update functions") Signed-off-by: Sebastian Andrzej Siewior Acked-by: Vlastimil Babka Acked-by: Shakeel Butt Acked-by: Michal Hocko Reviewed-by: Vlastimil Babka Cc: Johannes Weiner Cc: Muchun Song Cc: Roman Gushchin Cc: Thomas Gleixner Signed-off-by: Andrew Morton