KMSAN: uninit-value in atmtcp_c_send

Status: fixed on 2025/08/06 17:37
Subsystems: atm
[Documentation on labels]
Reported-by: syzbot+1d3c235276f62963e93a@syzkaller.appspotmail.com
Fix commit: 2f370ae1fb63 atm: atmtcp: Free invalid length skb in atmtcp_c_send().
First crash: 409d, last: 373d
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2 net 1/2] atm: atmtcp: Free invalid length skb in atmtcp_c_send(). 1 (1) 2025/06/16 18:21
[PATCH v1 net-next] atm: atmtcp: Free invalid length skb in atmtcp_c_send(). 3 (3) 2025/06/14 20:28
[syzbot] [atm?] KMSAN: uninit-value in atmtcp_c_send 3 (7) 2025/06/13 05:11
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in atmtcp_c_send atm 2 C done 7 334d 340d 29/29 fixed on 2025/10/09 01:15
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2025/06/13 04:24 30m kuni1840@gmail.com patch upstream OK log
2025/06/13 03:00 31m kuni1840@gmail.com patch upstream OK log
2025/06/12 23:49 1h25m kuni1840@gmail.com patch upstream error

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294
 atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294
 vcc_sendmsg+0xd7c/0xff0 net/atm/common.c:644
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655
 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4154 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4249
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1336 [inline]
 vcc_sendmsg+0xb40/0xff0 net/atm/common.c:628
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655
 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5798 Comm: syz-executor192 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
=====================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/12 22:50 upstream 2c4a1f3fe03e 98683f8f .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in atmtcp_c_send
2025/06/13 07:24 upstream 27605c8c0f69 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in atmtcp_c_send
2025/06/12 16:56 upstream 2c4a1f3fe03e 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in atmtcp_c_send
2025/07/19 09:33 net 96e056ffba91 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in atmtcp_c_send
2025/07/17 07:28 net 531d0d32de3e 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in atmtcp_c_send
2025/06/19 08:16 net f82727adcf29 ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in atmtcp_c_send
* Struck through repros no longer work on HEAD.