On Fri, Dec 22, 2023 at 12:11:21AM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 0e389834672c Merge tag 'for-6.7-rc5-tag' of git://git.kern.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1454824ee80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f21aff374937e60e > dashboard link: https://syzkaller.appspot.com/bug?extid=03fd9b3f71641f0ebf2d > compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b4ef49e80000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=118314d6e80000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/e58cd74e152a/disk-0e389834.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/45d17ccb34bc/vmlinux-0e389834.xz > kernel image: https://storage.googleapis.com/syzbot-assets/b9b7105d4e08/bzImage-0e389834.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+03fd9b3f71641f0ebf2d@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 5066 at mm/vmscan.c:3242 get_pte_pfn+0x1b5/0x3f0 mm/vmscan.c:3242 > Modules linked in: > CPU: 1 PID: 5066 Comm: syz-executor668 Not tainted 6.7.0-rc5-syzkaller-00270-g0e389834672c #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 > RIP: 0010:get_pte_pfn+0x1b5/0x3f0 mm/vmscan.c:3242 > Code: f3 74 2a e8 6d 78 cb ff 31 ff 48 b8 00 00 00 00 00 00 00 02 48 21 c5 48 89 ee e8 e6 73 cb ff 48 85 ed 74 4e e8 4c 78 cb ff 90 <0f> 0b 90 48 c7 c3 ff ff ff ff e8 3c 78 cb ff 48 b8 00 00 00 00 00 > RSP: 0018:ffffc900041e6878 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 000000000007891d RCX: ffffffff81bbf6e3 > RDX: ffff88807d813b80 RSI: ffffffff81bbf684 RDI: 0000000000000005 > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 > R10: 0000000000000200 R11: 0000000000000003 R12: 0000000000000200 > R13: 1ffff9200083cd0f R14: 0000000000010b21 R15: 0000000020ffc000 > FS: 0000555555f4d480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 000000005fbfa000 CR4: 0000000000350ef0 > Call Trace: > <TASK> > lru_gen_look_around+0x70d/0x11a0 mm/vmscan.c:4001 > folio_referenced_one+0x5a2/0xf70 mm/rmap.c:843 > rmap_walk_anon+0x225/0x570 mm/rmap.c:2485 > rmap_walk mm/rmap.c:2562 [inline] > rmap_walk mm/rmap.c:2557 [inline] > folio_referenced+0x28a/0x4b0 mm/rmap.c:960 > folio_check_references mm/vmscan.c:829 [inline] > shrink_folio_list+0x1ace/0x3f00 mm/vmscan.c:1160 > evict_folios+0x6e7/0x1b90 mm/vmscan.c:4499 > try_to_shrink_lruvec+0x638/0xa10 mm/vmscan.c:4704 > lru_gen_shrink_lruvec mm/vmscan.c:4849 [inline] > shrink_lruvec+0x314/0x2990 mm/vmscan.c:5622 > shrink_node_memcgs mm/vmscan.c:5842 [inline] > shrink_node+0x811/0x3710 mm/vmscan.c:5877 > shrink_zones mm/vmscan.c:6116 [inline] > do_try_to_free_pages+0x36c/0x1940 mm/vmscan.c:6178 #syz test diff --git a/mm/vmscan.c b/mm/vmscan.c index 9dd8977de5a2..041f9ad8f95b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3230,7 +3230,8 @@ static bool get_next_vma(unsigned long mask, unsigned long size, struct mm_walk return false; } -static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr) +static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr, + struct page *page) { unsigned long pfn = pte_pfn(pte); @@ -3239,8 +3240,14 @@ static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned if (!pte_present(pte) || is_zero_pfn(pfn)) return -1; - if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte))) + if (pte_devmap(pte) || pte_special(pte)) { + if (page) + dump_page(page, "get_pte_pfn()"); + dump_vma(vma); + dump_mm(vma->vm_mm); + BUG(); return -1; + } if (WARN_ON_ONCE(!pfn_valid(pfn))) return -1; @@ -3331,7 +3338,7 @@ static bool walk_pte_range(pmd_t *pmd, unsigned long start, unsigned long end, total++; walk->mm_stats[MM_LEAF_TOTAL]++; - pfn = get_pte_pfn(ptent, args->vma, addr); + pfn = get_pte_pfn(ptent, args->vma, addr, NULL); if (pfn == -1) continue; @@ -3998,7 +4005,7 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) unsigned long pfn; pte_t ptent = ptep_get(pte + i); - pfn = get_pte_pfn(ptent, pvmw->vma, addr); + pfn = get_pte_pfn(ptent, pvmw->vma, addr, pfn_to_page(pvmw->pfn)); if (pfn == -1) continue;
