From 2effe407f7563add41750fd7e03da4ea44b98099 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Fri, 19 Apr 2024 16:58:19 +0800 Subject: [PATCH] mm/hugetlb: fix DEBUG_LOCKS_WARN_ON(1) when dissolve_free_hugetlb_folio() commit 52ccdde16b6540abe43b6f8d8e1e1ec90b0983af upstream. When I did memory failure tests recently, below warning occurs: DEBUG_LOCKS_WARN_ON(1) WARNING: CPU: 8 PID: 1011 at kernel/locking/lockdep.c:232 __lock_acquire+0xccb/0x1ca0 Modules linked in: mce_inject hwpoison_inject CPU: 8 PID: 1011 Comm: bash Kdump: loaded Not tainted 6.9.0-rc3-next-20240410-00012-gdb69f219f4be #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:__lock_acquire+0xccb/0x1ca0 RSP: 0018:ffffa7a1c7fe3bd0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: eb851eb853975fcf RCX: ffffa1ce5fc1c9c8 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffffa1ce5fc1c9c0 RBP: ffffa1c6865d3280 R08: ffffffffb0f570a8 R09: 0000000000009ffb R10: 0000000000000286 R11: ffffffffb0f2ad50 R12: ffffa1c6865d3d10 R13: ffffa1c6865d3c70 R14: 0000000000000000 R15: 0000000000000004 FS: 00007ff9f32aa740(0000) GS:ffffa1ce5fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff9f3134ba0 CR3: 00000008484e4000 CR4: 00000000000006f0 Call Trace: lock_acquire+0xbe/0x2d0 _raw_spin_lock_irqsave+0x3a/0x60 hugepage_subpool_put_pages.part.0+0xe/0xc0 free_huge_folio+0x253/0x3f0 dissolve_free_huge_page+0x147/0x210 __page_handle_poison+0x9/0x70 memory_failure+0x4e6/0x8c0 hard_offline_page_store+0x55/0xa0 kernfs_fop_write_iter+0x12c/0x1d0 vfs_write+0x380/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xbc/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff9f3114887 RSP: 002b:00007ffecbacb458 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007ff9f3114887 RDX: 000000000000000c RSI: 0000564494164e10 RDI: 0000000000000001 RBP: 0000564494164e10 R08: 00007ff9f31d1460 R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 00007ff9f321b780 R14: 00007ff9f3217600 R15: 00007ff9f3216a00 Kernel panic - not syncing: kernel: panic_on_warn set ... CPU: 8 PID: 1011 Comm: bash Kdump: loaded Not tainted 6.9.0-rc3-next-20240410-00012-gdb69f219f4be #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: panic+0x326/0x350 check_panic_on_warn+0x4f/0x50 __warn+0x98/0x190 report_bug+0x18e/0x1a0 handle_bug+0x3d/0x70 exc_invalid_op+0x18/0x70 asm_exc_invalid_op+0x1a/0x20 RIP: 0010:__lock_acquire+0xccb/0x1ca0 RSP: 0018:ffffa7a1c7fe3bd0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: eb851eb853975fcf RCX: ffffa1ce5fc1c9c8 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffffa1ce5fc1c9c0 RBP: ffffa1c6865d3280 R08: ffffffffb0f570a8 R09: 0000000000009ffb R10: 0000000000000286 R11: ffffffffb0f2ad50 R12: ffffa1c6865d3d10 R13: ffffa1c6865d3c70 R14: 0000000000000000 R15: 0000000000000004 lock_acquire+0xbe/0x2d0 _raw_spin_lock_irqsave+0x3a/0x60 hugepage_subpool_put_pages.part.0+0xe/0xc0 free_huge_folio+0x253/0x3f0 dissolve_free_huge_page+0x147/0x210 __page_handle_poison+0x9/0x70 memory_failure+0x4e6/0x8c0 hard_offline_page_store+0x55/0xa0 kernfs_fop_write_iter+0x12c/0x1d0 vfs_write+0x380/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xbc/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff9f3114887 RSP: 002b:00007ffecbacb458 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007ff9f3114887 RDX: 000000000000000c RSI: 0000564494164e10 RDI: 0000000000000001 RBP: 0000564494164e10 R08: 00007ff9f31d1460 R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 00007ff9f321b780 R14: 00007ff9f3217600 R15: 00007ff9f3216a00 After git bisecting and digging into the code, I believe the root cause is that _deferred_list field of folio is unioned with _hugetlb_subpool field. In __update_and_free_hugetlb_folio(), folio->_deferred_list is initialized leading to corrupted folio->_hugetlb_subpool when folio is hugetlb. Later free_huge_folio() will use _hugetlb_subpool and above warning happens. But it is assumed hugetlb flag must have been cleared when calling folio_put() in update_and_free_hugetlb_folio(). This assumption is broken due to below race: CPU1 CPU2 dissolve_free_huge_page update_and_free_pages_bulk update_and_free_hugetlb_folio hugetlb_vmemmap_restore_folios folio_clear_hugetlb_vmemmap_optimized clear_flag = folio_test_hugetlb_vmemmap_optimized if (clear_flag) <-- False, it's already cleared. __folio_clear_hugetlb(folio) <-- Hugetlb is not cleared. folio_put free_huge_folio <-- free_the_page is expected. list_for_each_entry() __folio_clear_hugetlb <-- Too late. Fix this issue by checking whether folio is hugetlb directly instead of checking clear_flag to close the race window. Link: https://lkml.kernel.org/r/20240419085819.1901645-1-linmiaohe@huawei.com Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap") Signed-off-by: Miaohe Lin Reviewed-by: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Miaohe Lin Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e9ae0fc81dfb..4361dcf70139 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1762,7 +1762,6 @@ static void __update_and_free_page(struct hstate *h, struct page *page) { int i; struct page *subpage; - bool clear_dtor = HPageVmemmapOptimized(page); if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; @@ -1797,7 +1796,7 @@ static void __update_and_free_page(struct hstate *h, struct page *page) * If vmemmap pages were allocated above, then we need to clear the * hugetlb destructor under the hugetlb lock. */ - if (clear_dtor) { + if (PageHuge(page)) { spin_lock_irq(&hugetlb_lock); __clear_hugetlb_destructor(h, page); spin_unlock_irq(&hugetlb_lock);