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006d021491bc7-6949861f2a1mr1674480eaf.10.1776785662127; Tue, 21 Apr 2026 08:34:22 -0700 (PDT) Date: Tue, 21 Apr 2026 08:34:22 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e798fe.050a0220.24bfd3.0031.GAE@google.com> Subject: [syzbot] [net?] [nfs?] KASAN: slab-out-of-bounds Read in cache_seq_start_rcu From: syzbot To: Dai.Ngo@oracle.com, anna@kernel.org, chuck.lever@oracle.com, davem@davemloft.net, edumazet@google.com, horms@kernel.org, jlayton@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, neil@brown.name, netdev@vger.kernel.org, okorniev@redhat.com, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, tom@talpey.com, trondmy@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: b4e07588e743 tracing: tell git to ignore the generated 'un.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14b522d2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=45528449ee7e2c2f dashboard link: https://syzkaller.appspot.com/bug?extid=60cfa08822470bbebe44 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13f52c36580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13432cce580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c05a9c593011/disk-b4e07588.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/779dda6a7608/vmlinux-b4e07588.xz kernel image: https://storage.googleapis.com/syzbot-assets/5e7d794a3ff0/bzImage-b4e07588.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+60cfa08822470bbebe44@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-out-of-bounds in __cache_seq_start net/sunrpc/cache.c:1351 [inline] BUG: KASAN: slab-out-of-bounds in cache_seq_start_rcu+0x3fe/0x420 net/sunrpc/cache.c:1399 Read of size 8 at addr ffff88802ae92800 by task syz.0.17/6044 CPU: 1 UID: 0 PID: 6044 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595 __cache_seq_start net/sunrpc/cache.c:1351 [inline] cache_seq_start_rcu+0x3fe/0x420 net/sunrpc/cache.c:1399 seq_read_iter+0x2c1/0x1270 fs/seq_file.c:226 seq_read+0x33b/0x4c0 fs/seq_file.c:163 pde_read fs/proc/inode.c:308 [inline] proc_reg_read+0x240/0x330 fs/proc/inode.c:320 vfs_read+0x1e4/0xb30 fs/read_write.c:572 ksys_pread64 fs/read_write.c:765 [inline] __do_sys_pread64 fs/read_write.c:773 [inline] __se_sys_pread64 fs/read_write.c:770 [inline] __x64_sys_pread64+0x1eb/0x250 fs/read_write.c:770 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f88b8d9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc567f4a98 EFLAGS: 00000246 ORIG_RAX: 0000000000000011 RAX: ffffffffffffffda RBX: 00007f88b9015fa0 RCX: 00007f88b8d9c819 RDX: 0000000000000566 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f88b8e32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000080000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f88b9015fac R14: 00007f88b9015fa0 R15: 00007f88b9015fa0 Allocated by task 5958: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5295 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] cache_create_net+0xa2/0x1f0 net/sunrpc/cache.c:1733 nfsd_export_init+0x62/0x250 fs/nfsd/export.c:1536 nfsd_net_init+0x69/0x3e0 fs/nfsd/nfsctl.c:2209 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x118/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132 unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234 ksys_unshare+0x438/0xab0 kernel/fork.c:3245 __do_sys_unshare kernel/fork.c:3319 [inline] __se_sys_unshare kernel/fork.c:3317 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3317 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802ae92000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes to the right of allocated 2048-byte region [ffff88802ae92000, ffff88802ae92800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ae90 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813fe86000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe86000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5958, tgid 5958 (syz-executor), ts 108313513495, free_ts 108309100167 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7251 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5410 kmalloc_noprof include/linux/slab.h:950 [inline] netdev_create_hash net/core/dev.c:12922 [inline] netdev_init+0x151/0x3c0 net/core/dev.c:12942 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x118/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132 unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234 ksys_unshare+0x438/0xab0 kernel/fork.c:3245 __do_sys_unshare kernel/fork.c:3319 [inline] __se_sys_unshare kernel/fork.c:3317 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3317 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 page last free pid 5958 tgid 5958 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2943 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_node_noprof+0x25a/0x6f0 mm/slub.c:4950 __alloc_skb+0x140/0x710 net/core/skbuff.c:702 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] netlink_ack+0x117/0xb80 net/netlink/af_netlink.c:2487 netlink_rcv_skb+0x333/0x420 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x468/0x4b0 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2268 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802ae92700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88802ae92780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88802ae92800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88802ae92880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802ae92900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== --- This report is generated by a bot. 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