Public bug reported:
Note: I used an AI assistant to help interpret the crash and gather
background on CPU microarchitecture levels and the Go 1.26 toolchain. I
may have details wrong, so please verify. I just installed Ubuntu
yesterday and today Firefox and App Center was not opening today. I
installed Firefox through flatpak to post this issue.
Every snap operation crashes immediately with SIGILL (illegal instruction).
`snap list`, `snap version`, and all installed snaps (Firefox, App Center) are
affected. The stack trace points to the Go 1.26 runtime.
(IA interpretation of cause):
The CPU supports x86-64-v2 and v3 (AVX/AVX2) but not v4 (AVX-512). Go 1.26 can
now emit AVX-512 instructions via its new SIMD support. The snapd binary
appears to have been built targeting AVX-512 (GOAMD64=v4, or SIMD without
runtime CPU guards), so it executes AVX-512 opcodes that any non-v4 CPU rejects
with SIGILL. This affects the .deb binary as well — SNAP_REEXEC=0 does not
help, because /usr/bin/snap itself crashes before re-exec logic runs.
$ snap list
SIGILL: illegal instruction
PC=0x5deec487f220 m=0 sigcode=2
instruction bytes: 0xc4 0xe4 0x0 0x48 0x8d 0x5 0x96 0x35 0xcf 0x0 0xe8 0xd1
0x7c 0x72 0xff 0x44
goroutine 1 gp=0x343428341e0 m=0 mp=0x5deec56ce1a0 [running, locked to thread]:
crypto/internal/fips140/ecdsa.init()
/usr/lib/go-1.26/src/crypto/internal/fips140/ecdsa/ecdsa.go:149 +0x3e0
fp=0x34342905e28 sp=0x34342905dd8 pc=0x5deec487f220
runtime.doInit1(0x5deec5655170)
/usr/lib/go-1.26/src/runtime/proc.go:8103 +0xd7 fp=0x34342905f48
sp=0x34342905e28 pc=0x5deec3fe4197
runtime.doInit(...)
/usr/lib/go-1.26/src/runtime/proc.go:8070
runtime.main()
/usr/lib/go-1.26/src/runtime/proc.go:258 +0x270 fp=0x34342905fe0
sp=0x34342905f48 pc=0x5deec3fd47d0
runtime.goexit({})
/usr/lib/go-1.26/src/runtime/asm_amd64.s:1771 +0x1 fp=0x34342905fe8
sp=0x34342905fe0 pc=0x5deec4011921
goroutine 2 gp=0x34342834d20 m=nil [force gc (idle)]:
runtime.gopark(0x0?, 0x0?, 0x0?, 0x0?, 0x0?)
/usr/lib/go-1.26/src/runtime/proc.go:462 +0xce fp=0x343428eefa8
sp=0x343428eef88 pc=0x5deec4009f4e
runtime.goparkunlock(...)
/usr/lib/go-1.26/src/runtime/proc.go:468
runtime.forcegchelper()
/usr/lib/go-1.26/src/runtime/proc.go:375 +0xb8 fp=0x343428eefe0
sp=0x343428eefa8 pc=0x5deec3fd4b58
runtime.goexit({})
/usr/lib/go-1.26/src/runtime/asm_amd64.s:1771 +0x1 fp=0x343428eefe8
sp=0x343428eefe0 pc=0x5deec4011921
created by runtime.init.7 in goroutine 1
/usr/lib/go-1.26/src/runtime/proc.go:363 +0x1a
goroutine 3 gp=0x343428352c0 m=nil [GC sweep wait]:
runtime.gopark(0x0?, 0x0?, 0x0?, 0x0?, 0x0?)
/usr/lib/go-1.26/src/runtime/proc.go:462 +0xce fp=0x343428ef788
sp=0x343428ef768 pc=0x5deec4009f4e
runtime.goparkunlock(...)
/usr/lib/go-1.26/src/runtime/proc.go:468
runtime.bgsweep(0x34342876080)
/usr/lib/go-1.26/src/runtime/mgcsweep.go:279 +0x94 fp=0x343428ef7c8
sp=0x343428ef788 pc=0x5deec3fbe754
runtime.gcenable.gowrap1()
/usr/lib/go-1.26/src/runtime/mgc.go:214 +0x17 fp=0x343428ef7e0
sp=0x343428ef7c8 pc=0x5deec3fafb57
runtime.goexit({})
/usr/lib/go-1.26/src/runtime/asm_amd64.s:1771 +0x1 fp=0x343428ef7e8
sp=0x343428ef7e0 pc=0x5deec4011921
created by runtime.gcenable in goroutine 1
/usr/lib/go-1.26/src/runtime/mgc.go:214 +0x66
goroutine 4 gp=0x343428354a0 m=nil [GC scavenge wait]:
runtime.gopark(0x34342876080?, 0x5deec49d5fc8?, 0x1?, 0x0?, 0x343428354a0?)
/usr/lib/go-1.26/src/runtime/proc.go:462 +0xce fp=0x343428eff78
sp=0x343428eff58 pc=0x5deec4009f4e
runtime.goparkunlock(...)
/usr/lib/go-1.26/src/runtime/proc.go:468
runtime.(*scavengerState).park(0x5deec56cc7e0)
/usr/lib/go-1.26/src/runtime/mgcscavenge.go:425 +0x49 fp=0x343428effa8
sp=0x343428eff78 pc=0x5deec3fbc289
runtime.bgscavenge(0x34342876080)
/usr/lib/go-1.26/src/runtime/mgcscavenge.go:653 +0x3c fp=0x343428effc8
sp=0x343428effa8 pc=0x5deec3fbc7fc
runtime.gcenable.gowrap2()
/usr/lib/go-1.26/src/runtime/mgc.go:215 +0x17 fp=0x343428effe0
sp=0x343428effc8 pc=0x5deec3fafb17
runtime.goexit({})
/usr/lib/go-1.26/src/runtime/asm_amd64.s:1771 +0x1 fp=0x343428effe8
sp=0x343428effe0 pc=0x5deec4011921
created by runtime.gcenable in goroutine 1
/usr/lib/go-1.26/src/runtime/mgc.go:215 +0xa5
goroutine 5 gp=0x34342956000 m=nil [finalizer wait]:
runtime.gopark(0x5deec3fe4197?, 0x1c8?, 0x80?, 0x22?, 0x343428ee601?)
/usr/lib/go-1.26/src/runtime/proc.go:462 +0xce fp=0x343428ee620
sp=0x343428ee600 pc=0x5deec4009f4e
runtime.runFinalizers()
/usr/lib/go-1.26/src/runtime/mfinal.go:210 +0x107 fp=0x343428ee7e0
sp=0x343428ee620 pc=0x5deec3faeaa7
runtime.goexit({})
/usr/lib/go-1.26/src/runtime/asm_amd64.s:1771 +0x1 fp=0x343428ee7e8
sp=0x343428ee7e0 pc=0x5deec4011921
created by runtime.createfing in goroutine 1
/usr/lib/go-1.26/src/runtime/mfinal.go:172 +0x3d
rax 0x34342970050
rbx 0x50
rcx 0x0
rdx 0x0
rdi 0x0
rsi 0x1
rbp 0x34342905e18
rsp 0x34342905dd8
r8 0x73b1d68f5fe0
r9 0x50
r10 0xffffffffffffffff
r11 0x3434288c568
r12 0x34342970050
r13 0x64
r14 0x343428341e0
r15 0xffffffffffffffff
rip 0x5deec487f220
rflags 0x10202
cs 0x33
fs 0x0
gs 0x0
---
Additional information:
$ lsb_release -rd
Description: Ubuntu 26.04 LTS
Release: 26.04
$ dpkg -l snapd | tail -1
ii snapd 2.75.2+ubuntu26.04.2 amd64 Daemon and tooling that
enable snap packages
$ lscpu | grep 'Model name'
Model name: AMD Ryzen 9 5900X 12-Core Processor
$ /lib64/ld-linux-x86-64.so.2 --help | grep -i supported
x86-64-v3 (supported, searched)
x86-64-v2 (supported, searched)
$ objdump -d /usr/lib/snapd/snapd 2>/dev/null | grep -iE '%zmm|kmov' | head
331c00: 62 f1 fe 48 6f 08 vmovdqu64 (%rax),%zmm1
331c06: 62 f1 fe 48 6f 50 01 vmovdqu64 0x40(%rax),%zmm2
331c20: 62 f1 fe 48 6f 05 36 vmovdqu64 0xe54636(%rip),%zmm0 #
1186260 <crosscall2@@Base+0xca5880>
331c2a: 62 f1 fe 48 6f 0d 6c vmovdqu64 0xe5466c(%rip),%zmm1 #
11862a0 <crosscall2@@Base+0xca58c0>
331c34: 62 f1 fe 48 6f 15 a2 vmovdqu64 0xe546a2(%rip),%zmm2 #
11862e0 <crosscall2@@Base+0xca5900>
331c3e: 62 f1 fe 48 6f 1d d8 vmovdqu64 0xe56bd8(%rip),%zmm3 #
1188820 <crosscall2@@Base+0xca7e40>
331c48: 62 f1 fe 48 6f 20 vmovdqu64 (%rax),%zmm4
331c4e: 62 f2 7d 48 8d c4 vpermb %zmm4,%zmm0,%zmm0
331c54: 62 f3 fd 48 ce c1 00 vgf2p8affineqb $0x0,%zmm1,%zmm0,%zmm0
331c5b: 62 f2 6d 48 8d d4 vpermb %zmm4,%zmm2,%zmm2
** Affects: snapd (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2155805
Title:
snap commands crash with SIGILL on x86-64-v3 CPUs
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