CVE-2024-35886: In the Linux kernel, the following vulnerability has been resolved:  ipv6: Fix infinite recursion in fib6_dump_done().  syzkaller reported infinite recursive calls of fib6_dump_done() during netlink socket destruction.  [1]  From the log, syzkaller sent an AF_UNSPEC RTM_GETROUTE message, and then the response was generated.  The following recvmmsg() resumed the dump for IPv6, but the first call of inet6_dump_fib() failed at kzalloc() due to the fault injection.  [0]    12:01:34 executing program 3:   r0 = socket$nl_route(0x10, 0x3, 0x0)   sendmsg$nl_route(r0, ... snip ...)   recvmmsg(r0, ... snip ...) (fail_nth: 8)  Here, fib6_dump_done() was set to nlk_sk(sk)->cb.done, and the next call of inet6_dump_fib() set it to nlk_sk(sk)->cb.args[3].  syzkaller stopped receiving the response halfway through, and finally netlink_sock_destruct() called nlk_sk(sk)->cb.done().  fib6_dump_done() calls fib6_dump_end() and nlk_sk(sk)->cb.done() if it is still not NULL.  fib6_dump_end() rewrites nlk_sk(sk)->cb.done() by nlk_sk(sk)->cb.args[3], but it has the same function, not NULL, calling itself recursively and hitting the stack guard page.  To avoid the issue, let's set the destructor after kzalloc().  [0]: FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 432110 Comm: syz-executor.3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace:  <TASK>  dump_stack_lvl (lib/dump_stack.c:117)  should_fail_ex (lib/fault-inject.c:52 lib/fault-inject.c:153)  should_failslab (mm/slub.c:3733)  kmalloc_trace (mm/slub.c:3748 mm/slub.c:3827 mm/slub.c:3992)  inet6_dump_fib (./include/linux/slab.h:628 ./include/linux/slab.h:749 net/ipv6/ip6_fib.c:662)  rtnl_dump_all (net/core/rtnetlink.c:4029)  netlink_dump (net/netlink/af_netlink.c:2269)  netlink_recvmsg (net/netlink/af_netlink.c:1988)  ____sys_recvmsg (net/socket.c:1046 net/socket.c:2801)  ___sys_recvmsg (net/socket.c:2846)  do_recvmmsg (net/socket.c:2943)  __x64_sys_recvmmsg (net/socket.c:3041 net/socket.c:3034 net/socket.c:3034)  [1]: BUG: TASK stack guard page was hit at 00000000f2fa9af1 (stack is 00000000b7912430..000000009a436beb) stack guard page: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 223719 Comm: kworker/1:3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: events netlink_sock_destruct_work RIP: 0010:fib6_dump_done (net/ipv6/ip6_fib.c:570) Code: 3c 24 e8 f3 e9 51 fd e9 28 fd ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 41 57 41 56 41 55 41 54 55 48 89 fd <53> 48 8d 5d 60 e8 b6 4d 07 fd 48 89 da 48 b8 00 00 00 00 00 fc ff RSP: 0018:ffffc9000d980000 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffffff84405990 RCX: ffffffff844059d3 RDX: ffff8881028e0000 RSI: ffffffff84405ac2 RDI: ffff88810c02f358 RBP: ffff88810c02f358 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000224 R12: 0000000000000000 R13: ffff888007c82c78 R14: ffff888007c82c68 R15: ffff888007c82c68 FS:  0000000000000000(0000) GS:ffff88811b100000(0000) knlGS:0000000000000000 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc9000d97fff8 CR3: 0000000102309002 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace:  <#DF>  </#DF>  <TASK>  fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))  fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))  ...  fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))  fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))  netlink_sock_destruct (net/netlink/af_netlink.c:401)  __sk_destruct (net/core/sock.c:2177 (discriminator 2))  sk_destruct (net/core/sock.c:2224)  __sk_free (net/core/sock.c:2235)  sk_free (net/core/sock.c:2246)  process_one_work (kernel/workqueue.c:3259)  worker_thread (kernel/workqueue.c:3329 kernel/workqueue. ---truncated---