`steamwebhelper` crashes with SIGBUS (Signal 7) on KDE Wayland + NVIDIA on startup

steamclosed Distro Family: ArchWeb Component

ValveSoftware/steam-for-linux#12986 · opened 2026-03-15 by TillitschScHocK · updated 2026-03-21 · 2 comments · github

TTillitschScHocK 2026-03-15 github

System Information

OS: CachyOS (rolling) x86_64
Kernel: 6.19.7-1-cachyos
DE/WM: KDE Plasma 6.6.2 / KWin (Wayland)
GPU: NVIDIA GeForce RTX 3060 Ti
NVIDIA Driver: 580.142 (proprietary, DKMS)
Steam version: 1773426488 (built Mar 13 2026)
Display: 3840x1080 @ 120Hz (Ultrawide)

Description

After a system update on 2026-03-15, steamwebhelper crashes immediately on every startup with Signal 7 (SIGBUS). Steam enters a crash loop and never reaches the login screen. The issue persists regardless of:

-no-cef-sandbox
-cef-disable-gpu
-no-browser
-offline
LANG=C
STEAM_ENABLE_WAYLAND=1
STEAM_USE_XCOMPOSITE_WORKAROUND=0
Deleting ~/.local/share/Steam/config/htmlcache
Full reinstall of ~/.local/share/Steam and ~/.steam
Flatpak version of Steam (same crash)

Stack Trace (from journalctl)

Process 4172 (steamwebhelper) of user 1000 terminated abnormally with signal 7/BUS

#0  0x00007f71b1bf4286 n/a (libcef.so + 0x31f4286)
#1  0x00007f71b1c18230 n/a (libcef.so + 0x3218230)
#2  0x00007f71b1c2533c n/a (libcef.so + 0x322533c)
#3  0x00007f71b1bf4e67 n/a (libcef.so + 0x31f4e67)
#4  0x00007f71b1befd1e n/a (libcef.so + 0x31efd1e)
#5  0x00007f71b1befac1 n/a (libcef.so + 0x31efac1)
#6  0x00007f71b63f1dec n/a (libcef.so + 0x79f1dec)
#7  0x00007f71b63eece1 n/a (libcef.so + 0x79eece1)
#8  0x00007f71b63ef010 n/a (libcef.so + 0x79ef010)
#9  0x00007f71b63ef16c n/a (libcef.so + 0x79ef16c)
[#10](/issue/ValveSoftware/steam-for-linux/10) 0x00007f71b63ef1f6 n/a (libcef.so + 0x79ef1f6)
[#11](/issue/ValveSoftware/steam-for-linux/11) 0x00007f71b63e7202 n/a (libcef.so + 0x79e7202)
[#12](/issue/ValveSoftware/steam-for-linux/12) 0x00007f71b63e714d n/a (libcef.so + 0x79e714d)
[#13](/issue/ValveSoftware/steam-for-linux/13) 0x00007f71b63f35d1 n/a (libcef.so + 0x79f35d1)
[#14](/issue/ValveSoftware/steam-for-linux/14) 0x00007f71b63e66e5 n/a (libcef.so + 0x79e66e5)
[#15](/issue/ValveSoftware/steam-for-linux/15) 0x00007f71b65304c3 n/a (libcef.so + 0x7b304c3)
[#16](/issue/ValveSoftware/steam-for-linux/16) 0x00007f71b515ebaf n/a (libcef.so + 0x675ebaf)
[#17](/issue/ValveSoftware/steam-for-linux/17) 0x00007f71b5190021 n/a (libcef.so + 0x6790021)
[#18](/issue/ValveSoftware/steam-for-linux/18) 0x00007f71b518f9d4 n/a (libcef.so + 0x678f9d4)
[#19](/issue/ValveSoftware/steam-for-linux/19) 0x00007f71b518f5f9 n/a (libcef.so + 0x678f5f9)
[#20](/issue/ValveSoftware/steam-for-linux/20) 0x00007f71b5199a8e n/a (libcef.so + 0x6799a8e)
[#21](/issue/ValveSoftware/steam-for-linux/21) 0x00007f71b51997dd n/a (libcef.so + 0x67997dd)
[#22](/issue/ValveSoftware/steam-for-linux/22) 0x00007f71b51996ed n/a (libcef.so + 0x67996ed)
[#23](/issue/ValveSoftware/steam-for-linux/23) 0x00007f71b51b7963 n/a (libcef.so + 0x67b7963)

steamwebhelper launch command (from log):

./steamwebhelper -nocrashdialog -lang=en_US -cachedir=~/.local/share/Steam/config/htmlcache
-steampid=... -buildid=1773426488 -uimode=7 -startcount=0
-launcher=0 -use_xcomposite_workaround --valve-enable-site-isolation
--enable-smooth-scrolling --disable-gpu-compositing --disable-gpu
--password-store=basic --disable-quick-menu --disable-component-update
--disable-features=WinRetrieveSuggestionsOnlyOnDemand,SpareRendererForSitePerProcess,
DcheckIsFatal,BlockPromptsIfIgnoredOften,ValveFFmpegAllowLowDelayHEVC

Notes

The offsets in libcef.so are identical across every crash attempt, suggesting a deterministic code path
CEF Chrome version: 126.0.6478.183
/dev/shm is available and has sufficient space (7.8G free)
Same crash occurs with Flatpak Steam
Other CachyOS users report the same issue after the March 2026 update: https://discuss.cachyos.org/t/steam-not-launching-after-the-update-march/24697

Rrafaelbordoni-silva 2026-03-17 github

I literally just had this problem when everything was fine yesterday. Turns out earlier today, as I was trying to fix my keyboard being able to type accented letters correctly, I had setup these environment variables in order to use IBus:

GTK_IM_MODULE=wayland
XMODIFIERS=@im=ibus
QT_IM_MODULES=wayland;ibus
QT_IM_MODULE=ibus

I read to use those on the IBus Arch Wiki page. After looking through logs and errors messages, I saw some gtk errors on steamwebhelper and turns out removing those fixed the issue, steam is now launching normally. Also, turns KDE can handle IBus without the need for those env vars, so everything seems fine here.

TTillitschScHocK 2026-03-20 github

✅ Solved (at least for me) — KDE Community Theme was the culprit

Thanks for the tip, @rafaelbordoni-silva! Unfortunately removing those IBus environment variables didn't help in my case — they weren't set at all. But it pointed me in the right direction to look at environment-related causes more closely.

After days of debugging, reinstalling, and questioning my life choices, I found the actual culprit: I had a community theme applied to my KDE desktop, which apparently did not play nicely with Steam (or more specifically, with steamwebhelper). Switching back to the default KDE theme and restarting fixed the issue immediately — Steam launches without any crashes now.

So if you're on KDE and nothing else works: check your theme.
Sometimes the real villain wears a pretty coat. 🎨

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