On 6/3/25 3:40 AM, Stanislav Fomichev wrote:
FWIW, looking at the console log, the program that triggered the splat is:
447.453794ms ago: executing program 1 (id=2750):
bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, 0x0, 0x0)
syz_emit_ethernet(0x4a, &(0x7f0000000080)={@local, @link_local={0x1,
0x80, 0xc2, 0x0, 0x0, 0xe}, @void, {@ipv4={0x800, @tcp={{0x5, 0x4, 0x0,
0x0, 0x3c, 0x0, 0x0, 0x0, 0x6, 0x0, @rand_addr=0x64010102, @local},
{{0x4001, 0x0, 0x41424344, 0x41424344, 0x0, 0x6, 0xa, 0x0, 0x1, 0x0,
0x0, {[@md5sig={0x13, 0x12, "473ecfd2106a00"}]}}}}}}}, 0x0)
socketpair$unix(0x1, 0x3, 0x0,
&(0x7f0000000080)={<r0=>0xffffffffffffffff, <r1=>0xffffffffffffffff})
openat$audio(0xffffff9c, 0x0, 0x402, 0x0)
connect$unix(r0, &(0x7f000057eff8)=@abs, 0x6e)
sendmmsg$unix(r1, &(0x7f00000bd000), 0x318, 0x0)
recvmmsg(r0, &(0x7f00000000c0), 0x10106, 0x2, 0x0)
prctl$PR_SCHED_CORE(0x3e, 0x1, 0x0, 0x2, 0x0)
socket$netlink(0x10, 0x3, 0xe)
sendmsg(r1, &(0x7f0000000180)={0x0, 0x0, 0x0}, 0x0)
sched_setattr(0x0, &(0x7f0000000100)={0x38, 0x5, 0x0, 0x0, 0x0, 0xb49,
0x9, 0x8, 0x0, 0x3}, 0x0)
bpf$MAP_CREATE(0x0, 0x0, 0x0)
socketpair$unix(0x1, 0x1, 0x0, &(0x7f0000000240)={0xffffffffffffffff,
<r2=>0xffffffffffffffff})
ioctl$sock_SIOCETHTOOL(r2, 0x8946, &(0x7f0000000080)={'netdevsim0\x00',
&(0x7f0000000000)=@ethtool_sfeatures={0x3b, 0x2, [{0xfe}, {0xfffffff9}]}})
bpf$PROG_LOAD(0x5, 0x0, 0x0)
r3 = socket$netlink(0x10, 0x3, 0x10)
socketpair$unix(0x1, 0x3, 0x0, 0x0)
getsockopt$sock_cred(r3, 0x1, 0x11, &(0x7f0000000180)={0x0, <r4=>0x0,
<r5=>0x0}, &(0x7f0000000240)=0xc)
bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, &(0x7f00000006c0)={0x1, 0x4, 0x0,
&(0x7f0000000040)='GPL\x00', 0x8, 0x0, 0x0, 0x0, 0x0, '\x00', 0x0, 0x0,
0xffffffffffffffff, 0x8, 0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x10, 0x203, @void, @value}, 0x94)
r6 = syz_open_dev$sndctrl(&(0x7f0000000000), 0x1, 0x0)
ioctl$SNDRV_CTL_IOCTL_ELEM_READ(r6, 0xc4c85512, &(0x7f0000000280)={{0x6,
0x0, 0x0, 0x0, 'syz0\x00'}, 0x0, [0x0, 0x0, 0x0, 0xffffffffffffffff,
0xffffffefffffffff, 0x0, 0x3, 0x0, 0x0, 0x4, 0x0, 0x0,
0xffffffffbfffffff, 0x0, 0x0, 0x0, 0x3, 0x80000000, 0x3, 0x0, 0x0, 0x4,
0x0, 0x6, 0x0, 0x40, 0x0, 0xfffffffffffffffd, 0x100200000, 0x0, 0x0,
0x8, 0x0, 0x0, 0x9, 0x0, 0x10000, 0x1000, 0x0, 0x3, 0xfffffffffffffffd,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3, 0x0, 0x7, 0x10000, 0x7785, 0x0, 0x4,
0x4, 0x8, 0x0, 0xfffffffffffffffe, 0x0, 0x8, 0x0, 0x0, 0x80000000000,
0x0, 0x4, 0x0, 0xfffffffffffffffe, 0x0, 0x0, 0x0, 0xfffffffffffffffe,
0x0, 0x4000000000, 0x0, 0x80000000000000, 0x0, 0xfffffffffffffffc, 0x0,
0x0, 0xfffffffffffffffe, 0x0, 0x2000, 0x0, 0x0, 0x0, 0x0, 0x0,
0xfffffffffffffffd, 0x0, 0x0, 0x0, 0x100, 0x0, 0xfffffffffffffffd, 0x0,
0x0, 0x0, 0x2, 0x0, 0x0, 0x3, 0x2, 0x0, 0x0, 0xc0c0, 0x0, 0x0, 0x0, 0x0,
0x1, 0x0, 0x3, 0x0, 0xffffffffffeffffc, 0x0, 0x8000000000001, 0x0, 0x0,
0x0, 0x0, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0, 0x20000000, 0x0, 0x80]})
bind$netlink(r3, &(0x7f0000514ff4)={0x10, 0x0, 0x2, 0x2ff7afedf}, 0xc)
mmap(&(0x7f0000000000/0xb36000)=nil, 0xb36000, 0xb635773f06ebbeee,
0x8031, 0xffffffffffffffff, 0x0)
mlock(&(0x7f0000000000/0x800000)=nil, 0x800000)
madvise(&(0x7f0000000000/0x600000)=nil, 0x600003, 0x19)
mount$fuse(0x0, 0x0, &(0x7f0000002100), 0x0, &(0x7f00000008c0)={{},
0x2c, {'rootmode', 0x3d, 0x4000}, 0x2c, {'user_id', 0x3d, r4}, 0x2c, {},
0x2c, {[{@blksize={'blksize', 0x3d, 0x1000}}, {@max_read={'max_read',
0x3d, 0x3}}, {@blksize={'blksize', 0x3d, 0x1000}},
{@max_read={'max_read', 0x3d, 0x3}}, {@blksize={'blksize', 0x3d,
0x1400}}, {@blksize}]}})
read$FUSE(0xffffffffffffffff, &(0x7f0000006380)={0x2020, 0x0, 0x0, 0x0,
<r7=>0x0}, 0x2020)
r8 = socket(0x10, 0x2, 0x0)
ioctl$KVM_SET_PIT(0xffffffffffffffff, 0x4048aec9,
&(0x7f0000000080)={[{0x80000000, 0x0, 0x0, 0x3, 0x0, 0x10, 0x6, 0x0,
0x2, 0x0, 0xa, 0x0, 0x4}, {0xa, 0x0, 0x0, 0x0, 0x40, 0x1, 0x8, 0xff,
0x7, 0x0, 0x4, 0x0, 0xfffffffffffffff7}, {0x200000, 0xc, 0x21, 0x53,
0x0, 0x2, 0x0, 0x0, 0x58, 0xb, 0x0, 0x0, 0x8080}], 0x3fb})
sendmsg$nl_route(r8, &(0x7f0000000140)={0x0, 0x0,
&(0x7f0000000100)={&(0x7f0000000780)=ANY=[@ANYBLOB="2ea8d2811b2a246ba8a8a78787aee7bb20c96807b6d8761f859ec6fa331e777591ed11248a94c0cfc19c61fe7c081ddaf685d4d5b414a01ac8d511cfb5d75e8878514da879142e585b1f9213b0f04d67baae20dd2e742f1286afc7a9bb0ad44aa05e2e3db382651792f2945409e7c6dda83d14fef1fb50a3cb8d0a189d28277f501a04c5d4414479db27bd23c1fbdf28124c317129fe42ebf9",
@ANYRES8, @ANYRES64, @ANYRESOCT=r2, @ANYRES32, @ANYRES16=r7,
@ANYRESDEC=r5], 0x30}, 0x1, 0x0, 0x0, 0xc885}, 0x4000880)
and the suspect ethtool operation should be:
ioctl$sock_SIOCETHTOOL(r2, 0x8946, &(0x7f0000000080)={'netdevsim0\x00',
&(0x7f0000000000)=@ethtool_sfeatures={0x3b, 0x2, [{0xfe}, {0xfffffff9}]}})
Since syzkaller has no reproducer, I guess the splat depends on some
additional state/race, but I don't see how/where the lower -> bond ->
lowers features update chain is (should be) interrupted to break this
double lock.
/P