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akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 31, 2022 at 11:31 AM Yang Shi wrote: > > Syzbot reported the below splat: > > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 __alloc_pages_node include/linux/gfp.h:221 [inline] > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 > Modules linked in: > CPU: 1 PID: 3646 Comm: syz-executor210 Not tainted 6.1.0-rc1-syzkaller-00454-ga70385240892 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 > RIP: 0010:__alloc_pages_node include/linux/gfp.h:221 [inline] > RIP: 0010:hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] > RIP: 0010:alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 > Code: e5 01 4c 89 ee e8 6e f9 ae ff 4d 85 ed 0f 84 28 fc ff ff e8 70 fc ae ff 48 8d 6b ff 4c 8d 63 07 e9 16 fc ff ff e8 5e fc ae ff <0f> 0b e9 96 fa ff ff 41 bc 1a 00 00 00 e9 86 fd ff ff e8 47 fc ae > RSP: 0018:ffffc90003fdf7d8 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff888077f457c0 RSI: ffffffff81cd8f42 RDI: 0000000000000001 > RBP: ffff888079388c0c R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 > FS: 00007f6b48ccf700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f6b48a819f0 CR3: 00000000171e7000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > collapse_file+0x1ca/0x5780 mm/khugepaged.c:1715 > hpage_collapse_scan_file+0xd6c/0x17a0 mm/khugepaged.c:2156 > madvise_collapse+0x53a/0xb40 mm/khugepaged.c:2611 > madvise_vma_behavior+0xd0a/0x1cc0 mm/madvise.c:1066 > madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1240 > do_madvise.part.0+0x24a/0x340 mm/madvise.c:1419 > do_madvise mm/madvise.c:1432 [inline] > __do_sys_madvise mm/madvise.c:1432 [inline] > __se_sys_madvise mm/madvise.c:1430 [inline] > __x64_sys_madvise+0x113/0x150 mm/madvise.c:1430 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f6b48a4eef9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f6b48ccf318 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 00007f6b48af0048 RCX: 00007f6b48a4eef9 > RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000 > RBP: 00007f6b48af0040 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6b48aa53a4 > R13: 00007f6b48bffcbf R14: 00007f6b48ccf400 R15: 0000000000022000 > > > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 __alloc_pages_node > include/linux/gfp.h:221 [inline] > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 > hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] > WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 > alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 > Modules linked in: > CPU: 1 PID: 3646 Comm: syz-executor210 Not tainted > 6.1.0-rc1-syzkaller-00454-ga70385240892 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 10/11/2022 > RIP: 0010:__alloc_pages_node include/linux/gfp.h:221 [inline] > RIP: 0010:hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] > RIP: 0010:alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 > Code: e5 01 4c 89 ee e8 6e f9 ae ff 4d 85 ed 0f 84 28 fc ff ff e8 70 fc > ae ff 48 8d 6b ff 4c 8d 63 07 e9 16 fc ff ff e8 5e fc ae ff <0f> 0b e9 > 96 fa ff ff 41 bc 1a 00 00 00 e9 86 fd ff ff e8 47 fc ae > RSP: 0018:ffffc90003fdf7d8 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffff888077f457c0 RSI: ffffffff81cd8f42 RDI: 0000000000000001 > RBP: ffff888079388c0c R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 > FS: 00007f6b48ccf700(0000) GS:ffff8880b9b00000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f6b48a819f0 CR3: 00000000171e7000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > collapse_file+0x1ca/0x5780 mm/khugepaged.c:1715 > hpage_collapse_scan_file+0xd6c/0x17a0 mm/khugepaged.c:2156 > madvise_collapse+0x53a/0xb40 mm/khugepaged.c:2611 > madvise_vma_behavior+0xd0a/0x1cc0 mm/madvise.c:1066 > madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1240 > do_madvise.part.0+0x24a/0x340 mm/madvise.c:1419 > do_madvise mm/madvise.c:1432 [inline] > __do_sys_madvise mm/madvise.c:1432 [inline] > __se_sys_madvise mm/madvise.c:1430 [inline] > __x64_sys_madvise+0x113/0x150 mm/madvise.c:1430 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f6b48a4eef9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89 > f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 > f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f6b48ccf318 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 00007f6b48af0048 RCX: 00007f6b48a4eef9 > RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000 > RBP: 00007f6b48af0040 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6b48aa53a4 > R13: 00007f6b48bffcbf R14: 00007f6b48ccf400 R15: 0000000000022000 > > > It is because khugepaged allocates pages with __GFP_THISNODE, but the > preferred node is offlined. The warning was even stronger before commit > 8addc2d00fe17 ("mm: do not warn on offline nodes unless the specific node > is explicitly requested"). The commit softened the warning for > __GFP_THISNODE. > > But this warning seems not quite useful because: > * There is no guarantee the node is online for __GFP_THISNODE context > for all the callsites. > * Kernel just fails the allocation regardless the warning, and it looks > all callsites handle the allocation failure gracefully. > > So, removing the warning seems like the good move. > > Reported-by: syzbot+0044b22d177870ee974f@syzkaller.appspotmail.com > Signed-off-by: Yang Shi > Cc: Zach O'Keefe > Cc: Michal Hocko Reviewed-by: Zach O'Keefe > --- > include/linux/gfp.h | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index ef4aea3b356e..594d6dee5646 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -218,7 +218,6 @@ static inline struct page * > __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int order) > { > VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES); > - VM_WARN_ON((gfp_mask & __GFP_THISNODE) && !node_online(nid)); > > return __alloc_pages(gfp_mask, order, nid, NULL); > } > @@ -227,7 +226,6 @@ static inline > struct folio *__folio_alloc_node(gfp_t gfp, unsigned int order, int nid) > { > VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES); > - VM_WARN_ON((gfp & __GFP_THISNODE) && !node_online(nid)); > > return __folio_alloc(gfp, order, nid, NULL); > } > -- > 2.26.3 >