CVE-2024-26855 – net: ice: Fix potential NULL pointer dereference in ice_bridge_setlink()
https://notcve.org/view.php?id=CVE-2024-26855
In the Linux kernel, the following vulnerability has been resolved: net: ice: Fix potential NULL pointer dereference in ice_bridge_setlink() The function ice_bridge_setlink() may encounter a NULL pointer dereference if nlmsg_find_attr() returns NULL and br_spec is dereferenced subsequently in nla_for_each_nested(). To address this issue, add a check to ensure that br_spec is not NULL before proceeding with the nested attribute iteration. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: ice: corrige una posible desreferencia de puntero NULL en ice_bridge_setlink() La función ice_bridge_setlink() puede encontrar una desreferencia de puntero NULL si nlmsg_find_attr() devuelve NULL y br_spec se desreferencia posteriormente en nla_for_each_nested( ). Para solucionar este problema, agregue una verificación para garantizar que br_spec no sea NULL antes de continuar con la iteración del atributo anidado. A vulnerability was found in the ice_bridge_setlink() function in the Linux kernel. • https://git.kernel.org/stable/c/b1edc14a3fbfe0154a2aecb8bb9775c3012cb6e2 https://git.kernel.org/stable/c/d9fefc51133107e59d192d773be86c1150cfeebb https://git.kernel.org/stable/c/37fe99016b12d32100ce670216816dba6c48b309 https://git.kernel.org/stable/c/8d95465d9a424200485792858c5b3be54658ce19 https://git.kernel.org/stable/c/afdd29726a6de4ba27cd15590661424c888dc596 https://git.kernel.org/stable/c/1a770927dc1d642b22417c3e668c871689fc58b3 https://git.kernel.org/stable/c/0e296067ae0d74a10b4933601f9aa9f0ec8f157f https://git.kernel.org/stable/c/06e456a05d669ca30b224b8ed96242177 • CWE-690: Unchecked Return Value to NULL Pointer Dereference •
CVE-2024-26853 – igc: avoid returning frame twice in XDP_REDIRECT
https://notcve.org/view.php?id=CVE-2024-26853
In the Linux kernel, the following vulnerability has been resolved: igc: avoid returning frame twice in XDP_REDIRECT When a frame can not be transmitted in XDP_REDIRECT (e.g. due to a full queue), it is necessary to free it by calling xdp_return_frame_rx_napi. However, this is the responsibility of the caller of the ndo_xdp_xmit (see for example bq_xmit_all in kernel/bpf/devmap.c) and thus calling it inside igc_xdp_xmit (which is the ndo_xdp_xmit of the igc driver) as well will lead to memory corruption. In fact, bq_xmit_all expects that it can return all frames after the last successfully transmitted one. Therefore, break for the first not transmitted frame, but do not call xdp_return_frame_rx_napi in igc_xdp_xmit. This is equally implemented in other Intel drivers such as the igb. There are two alternatives to this that were rejected: 1. Return num_frames as all the frames would have been transmitted and release them inside igc_xdp_xmit. While it might work technically, it is not what the return value is meant to represent (i.e. the number of SUCCESSFULLY transmitted packets). 2. Rework kernel/bpf/devmap.c and all drivers to support non-consecutively dropped packets. Besides being complex, it likely has a negative performance impact without a significant gain since it is anyway unlikely that the next frame can be transmitted if the previous one was dropped. The memory corruption can be reproduced with the following script which leads to a kernel panic after a few seconds. It basically generates more traffic than a i225 NIC can transmit and pushes it via XDP_REDIRECT from a virtual interface to the physical interface where frames get dropped. #!/bin/bash INTERFACE=enp4s0 INTERFACE_IDX=`cat /sys/class/net/$INTERFACE/ifindex` sudo ip link add dev veth1 type veth peer name veth2 sudo ip link set up $INTERFACE sudo ip link set up veth1 sudo ip link set up veth2 cat << EOF > redirect.bpf.c SEC("prog") int redirect(struct xdp_md *ctx) { return bpf_redirect($INTERFACE_IDX, 0); } char _license[] SEC("license") = "GPL"; EOF clang -O2 -g -Wall -target bpf -c redirect.bpf.c -o redirect.bpf.o sudo ip link set veth2 xdp obj redirect.bpf.o cat << EOF > pass.bpf.c SEC("prog") int pass(struct xdp_md *ctx) { return XDP_PASS; } char _license[] SEC("license") = "GPL"; EOF clang -O2 -g -Wall -target bpf -c pass.bpf.c -o pass.bpf.o sudo ip link set $INTERFACE xdp obj pass.bpf.o cat << EOF > trafgen.cfg { /* Ethernet Header */ 0xe8, 0x6a, 0x64, 0x41, 0xbf, 0x46, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, const16(ETH_P_IP), /* IPv4 Header */ 0b01000101, 0, # IPv4 version, IHL, TOS const16(1028), # IPv4 total length (UDP length + 20 bytes (IP header)) const16(2), # IPv4 ident 0b01000000, 0, # IPv4 flags, fragmentation off 64, # IPv4 TTL 17, # Protocol UDP csumip(14, 33), # IPv4 checksum /* UDP Header */ 10, 0, 1, 1, # IP Src - adapt as needed 10, 0, 1, 2, # IP Dest - adapt as needed const16(6666), # UDP Src Port const16(6666), # UDP Dest Port const16(1008), # UDP length (UDP header 8 bytes + payload length) csumudp(14, 34), # UDP checksum /* Payload */ fill('W', 1000), } EOF sudo trafgen -i trafgen.cfg -b3000MB -o veth1 --cpp En el kernel de Linux se ha resuelto la siguiente vulnerabilidad: igc: evita devolver la trama dos veces en XDP_REDIRECT Cuando una trama no se puede transmitir en XDP_REDIRECT (por ejemplo, debido a una cola llena), es necesario liberarla llamando a xdp_return_frame_rx_napi. • https://git.kernel.org/stable/c/4ff3203610928cac82d5627ce803559e78d61b91 https://git.kernel.org/stable/c/63a3c1f3c9ecc654d851e7906d05334cd0c236e2 https://git.kernel.org/stable/c/8df393af9e7e8dfd62e9c41dbaa4d2ff53bf794a https://git.kernel.org/stable/c/1b3b8231386a572bac8cd5b6fd7e944b84f9bb1f https://git.kernel.org/stable/c/ef27f655b438bed4c83680e4f01e1cde2739854b https://access.redhat.com/security/cve/CVE-2024-26853 https://bugzilla.redhat.com/show_bug.cgi?id=2275748 • CWE-20: Improper Input Validation •
CVE-2024-26852 – net/ipv6: avoid possible UAF in ip6_route_mpath_notify()
https://notcve.org/view.php?id=CVE-2024-26852
In the Linux kernel, the following vulnerability has been resolved: net/ipv6: avoid possible UAF in ip6_route_mpath_notify() syzbot found another use-after-free in ip6_route_mpath_notify() [1] Commit f7225172f25a ("net/ipv6: prevent use after free in ip6_route_mpath_notify") was not able to fix the root cause. We need to defer the fib6_info_release() calls after ip6_route_mpath_notify(), in the cleanup phase. [1] BUG: KASAN: slab-use-after-free in rt6_fill_node+0x1460/0x1ac0 Read of size 4 at addr ffff88809a07fc64 by task syz-executor.2/23037 CPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x167/0x540 mm/kasan/report.c:488 kasan_report+0x142/0x180 mm/kasan/report.c:601 rt6_fill_node+0x1460/0x1ac0 inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184 ip6_route_mpath_notify net/ipv6/route.c:5198 [inline] ip6_route_multipath_add net/ipv6/route.c:5404 [inline] inet6_rtm_newroute+0x1d0f/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f73dd87dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858 </TASK> Allocated by task 23037: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:372 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:3981 [inline] __kmalloc+0x22e/0x490 mm/slub.c:3994 kmalloc include/linux/slab.h:594 [inline] kzalloc include/linux/slab.h:711 [inline] fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758 ip6_route_multipath_add net/ipv6/route.c:5298 [inline] inet6_rtm_newroute+0x744/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 Freed by task 16: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640 poison_slab_object+0xa6/0xe0 m ---truncated--- En el kernel de Linux se ha resuelto la siguiente vulnerabilidad: net/ipv6: evita posible UAF en ip6_route_mpath_notify() syzbot encontró otro use-after-free en ip6_route_mpath_notify() [1] Commit f7225172f25a ("net/ipv6: previene el use-after-free in ip6_route_mpath_notify") no pudo solucionar la causa raíz. Necesitamos diferir las llamadas a fib6_info_release() después de ip6_route_mpath_notify(), en la fase de limpieza. [1] ERROR: KASAN: slab-use-after-free en rt6_fill_node+0x1460/0x1ac0 Lectura de tamaño 4 en la dirección ffff88809a07fc64 mediante la tarea syz-executor.2/23037 CPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 25/01/2024 Seguimiento de llamadas: __dump_stack lib/dump_stack.c:88 [en línea] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [en línea] print_report+0x167/0x540 mm/kasan/report.c:488 kasan_report+0x142/0x180 mm/kasan/report. c:601 rt6_fill_node+0x1460/0x1ac0 inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184 ip6_route_mpath_notify net/ipv6/route.c:5198 [en línea] ip6_route_multipath_add net/ipv6/route.c:5404 et6_rtm_nuevaruta+ 0x1d0f/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1 341 [en línea] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg+0x221/0x270 net/socket .c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [en línea] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entrada_SYSC ALL_64_after_hwframe+0x6f/0x77 RIP : 0033:0x7f73dd87dda9 Código: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 24 08 0f 05 <48 > 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: de RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858 Asignado por tarea 23037: kasan_save_stack mm/kasan/common.c:47 [en línea] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 veneno_kmalloc_redzone mm/kasan/common.c:372 [en línea] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389 kasan_kmalloc include/linux/kasan.h: 211 [en línea] __do_kmalloc_node mm/slub.c:3981 [en línea] __kmalloc+0x22e/0x490 mm/slub.c:3994 kmalloc include/linux/slab.h:594 [en línea] kzalloc include/linux/slab.h:711 [en línea] fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758 ip6_route_multipath_add net/ipv6/route.c:5298 [inet6_rtm_newroute+0x74 4/0x2300 neto /ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [en línea] netlink_unicast +0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [en línea] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entrada_SYSCALL_64_after_ hwframe+0x6f/0x77 Liberado por la tarea 16: kasan_save_stack mm/kasan/common.c:47 [en línea] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640 veneno_slab_object+0xa6/0xe0 m --- truncado--- A use-after-free flaw was found in ip6_route_mpath_notify() in the Linux kernel. This may lead to a crash. • https://git.kernel.org/stable/c/3b1137fe74829e021f483756a648cbb87c8a1b4a https://git.kernel.org/stable/c/31ea5bcc7d4cd1423de6be327a2c034725704136 https://git.kernel.org/stable/c/664f9c647260cc9d68b4e31d9899530d89dd045e https://git.kernel.org/stable/c/79ce2e54cc0ae366f45516c00bf1b19aa43e9abe https://git.kernel.org/stable/c/cae3303257950d03ffec2df4a45e836f10d26c24 https://git.kernel.org/stable/c/394334fe2ae3b9f1e2332b873857e84cb28aac18 https://git.kernel.org/stable/c/ed883060c38721ed828061f6c0c30e5147326c9a https://git.kernel.org/stable/c/61b34f73cdbdb8eaf9ea12e9e2eb3b297 • CWE-416: Use After Free •
CVE-2024-26851 – netfilter: nf_conntrack_h323: Add protection for bmp length out of range
https://notcve.org/view.php?id=CVE-2024-26851
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: Add protection for bmp length out of range UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts that are out of bounds for their data type. vmlinux get_bitmap(b=75) + 712 <net/netfilter/nf_conntrack_h323_asn1.c:0> vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956 <net/netfilter/nf_conntrack_h323_asn1.c:592> vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812 <net/netfilter/nf_conntrack_h323_asn1.c:576> vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux DecodeRasMessage() + 304 <net/netfilter/nf_conntrack_h323_asn1.c:833> vmlinux ras_help() + 684 <net/netfilter/nf_conntrack_h323_main.c:1728> vmlinux nf_confirm() + 188 <net/netfilter/nf_conntrack_proto.c:137> Due to abnormal data in skb->data, the extension bitmap length exceeds 32 when decoding ras message then uses the length to make a shift operation. It will change into negative after several loop. UBSAN load could detect a negative shift as an undefined behaviour and reports exception. So we add the protection to avoid the length exceeding 32. Or else it will return out of range error and stop decoding. En el kernel de Linux, se resolvió la siguiente vulnerabilidad: netfilter: nf_conntrack_h323: Agregar protección para longitud de bmp fuera de rango La carga de UBSAN informa una excepción de BRK#5515 SHIFT_ISSUE: desplazamientos bit a bit que están fuera de los límites para su tipo de datos. vmlinux get_bitmap(b=75) + 712 vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, nivel=134443100) + 1956 vmlinux decode_choice (base=0xFFFFFFD0080370F0, nivel=23843636) + 1216 vmlinux decode_seq(f=0xFFFFFFD0080371A8, nivel=134443500) + 812 vmlinux decode_choice(base =0xFFFFFFD008037280, nivel=0) + 1216 vmlinux DecodeRasMessage() + 304 vmlinux ras_help() + 684 vmlinux nf_confirm() + 188 Debido a datos anormales en skb->data, la longitud del mapa de bits de la extensión excede 32 cuando se decodifica el mensaje ras y luego usa la longitud para realizar una operación de cambio . Cambiará a negativo después de varios bucles. • https://git.kernel.org/stable/c/5e35941d990123f155b02d5663e51a24f816b6f3 https://git.kernel.org/stable/c/98db42191329c679f4ca52bec0b319689e1ad8cb https://git.kernel.org/stable/c/4bafcc43baf7bcf93566394dbd15726b5b456b7a https://git.kernel.org/stable/c/ccd1108b16ab572d9bf635586b0925635dbd6bbc https://git.kernel.org/stable/c/b3c0f553820516ad4b62a9390ecd28d6f73a7b13 https://git.kernel.org/stable/c/39001e3c42000e7c2038717af0d33c32319ad591 https://git.kernel.org/stable/c/014a807f1cc9c9d5173c1cd935835553b00d211c https://git.kernel.org/stable/c/80ee5054435a11c87c9a4f30f1ff75008 • CWE-20: Improper Input Validation •
CVE-2024-26850 – mm/debug_vm_pgtable: fix BUG_ON with pud advanced test
https://notcve.org/view.php?id=CVE-2024-26850
In the Linux kernel, the following vulnerability has been resolved: mm/debug_vm_pgtable: fix BUG_ON with pud advanced test Architectures like powerpc add debug checks to ensure we find only devmap PUD pte entries. These debug checks are only done with CONFIG_DEBUG_VM. This patch marks the ptes used for PUD advanced test devmap pte entries so that we don't hit on debug checks on architecture like ppc64 as below. WARNING: CPU: 2 PID: 1 at arch/powerpc/mm/book3s64/radix_pgtable.c:1382 radix__pud_hugepage_update+0x38/0x138 .... NIP [c0000000000a7004] radix__pud_hugepage_update+0x38/0x138 LR [c0000000000a77a8] radix__pudp_huge_get_and_clear+0x28/0x60 Call Trace: [c000000004a2f950] [c000000004a2f9a0] 0xc000000004a2f9a0 (unreliable) [c000000004a2f980] [000d34c100000000] 0xd34c100000000 [c000000004a2f9a0] [c00000000206ba98] pud_advanced_tests+0x118/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 Also kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:202! .... NIP [c000000000096510] pudp_huge_get_and_clear_full+0x98/0x174 LR [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 Call Trace: [c000000004a2f950] [000d34c100000000] 0xd34c100000000 (unreliable) [c000000004a2f9a0] [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mm/debug_vm_pgtable: corrige BUG_ON con la prueba avanzada de pud. Las arquitecturas como powerpc agregan comprobaciones de depuración para garantizar que solo encontremos entradas devmap PUD pte. Estas comprobaciones de depuración sólo se realizan con CONFIG_DEBUG_VM. • https://git.kernel.org/stable/c/27af67f35631ac4b61b5e4455b44c9aee8d2cc4b https://git.kernel.org/stable/c/d2a9510c0e39d06f5544075c13040407bdbf2803 https://git.kernel.org/stable/c/eeeddf85fc58d48c58ad916e4ca12363ebd8ab21 https://git.kernel.org/stable/c/720da1e593b85a550593b415bf1d79a053133451 •