syzbot


BUG: unable to handle kernel NULL pointer dereference in tcp_bpf_sendmsg

Status: upstream: reported on 2024/08/27 08:43
Subsystems: bpf net
[Documentation on labels]
Reported-by: syzbot+7449cfb801474783f727@syzkaller.appspotmail.com
First crash: 53d, last: 51d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] [net?] BUG: unable to handle kernel NULL pointer dereference in tcp_bpf_sendmsg 0 (1) 2024/08/27 08:43

Sample crash report:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 52-bit VAs, pgdp=0000000043fd4f00
[0000000000000000] pgd=080000004882a003, p4d=080000005bba7003, pud=080000004a4bd003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 UID: 0 PID: 23032 Comm: syz.0.5798 Not tainted 6.11.0-rc4-syzkaller-00222-g7eb61cc674ee #0
Hardware name: linux,dummy-virt (DT)
pstate: 81400009 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : page_kasan_tag include/linux/mm.h:1816 [inline]
pc : lowmem_page_address include/linux/mm.h:2254 [inline]
pc : sg_virt include/linux/scatterlist.h:404 [inline]
pc : sk_msg_memcopy_from_iter+0x134/0x1e0 net/core/skmsg.c:389
lr : tcp_bpf_sendmsg+0x1f4/0x8d0 net/ipv4/tcp_bpf.c:541
sp : ffff800088013720
x29: ffff800088013720 x28: faf0000010f136c0 x27: fcf000001bb93200
x26: 000000000000018c x25: fdf00000242bc400 x24: 0000000000000001
x23: 0000000000000000 x22: ffff801000000000 x21: 00003e0040000000
x20: fff0000000000000 x19: ffff800088013da0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000020001100
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: f8f0000008d11ce0 x10: 0000000000000000 x9 : 0000000000000000
x8 : ffff800088013af8 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000000 x4 : fdf00000242bc440 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 arch_static_branch_jump arch/arm64/include/asm/jump_label.h:46 [inline]
 kasan_enabled include/linux/kasan-enabled.h:13 [inline]
 page_kasan_tag include/linux/mm.h:1815 [inline]
 lowmem_page_address include/linux/mm.h:2254 [inline]
 sg_virt include/linux/scatterlist.h:404 [inline]
 sk_msg_memcopy_from_iter+0x134/0x1e0 net/core/skmsg.c:389
 tcp_bpf_sendmsg+0x1f4/0x8d0 net/ipv4/tcp_bpf.c:541
 inet6_sendmsg+0x44/0x70 net/ipv6/af_inet6.c:661
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x54/0x60 net/socket.c:745
 ____sys_sendmsg+0x274/0x2ac net/socket.c:2597
 ___sys_sendmsg+0xac/0x100 net/socket.c:2651
 __sys_sendmsg+0x84/0xe0 net/socket.c:2680
 __do_sys_sendmsg net/socket.c:2689 [inline]
 __se_sys_sendmsg net/socket.c:2687 [inline]
 __arm64_sys_sendmsg+0x24/0x30 net/socket.c:2687
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x48/0x110 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151
 el0_svc+0x34/0xec arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:598
Code: d346fed6 1a9a92f7 8b163296 d503201f (f9400001) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	d346fed6 	lsr	x22, x22, #6
   4:	1a9a92f7 	csel	w23, w23, w26, ls	// ls = plast
   8:	8b163296 	add	x22, x20, x22, lsl #12
   c:	d503201f 	nop
* 10:	f9400001 	ldr	x1, [x0] <-- trapping instruction

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/24 13:22 upstream 7eb61cc674ee d7d32352 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte BUG: unable to handle kernel NULL pointer dereference in tcp_bpf_sendmsg
2024/08/22 19:25 upstream 872cf28b8df9 aa99fc33 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte BUG: unable to handle kernel NULL pointer dereference in tcp_bpf_sendmsg
* Struck through repros no longer work on HEAD.