Same issue. Firefox 129.0.1 Ubuntu 24.04
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/cpu0/cache/index2/size
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/cpu0/cache/index3/size
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/present
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/possible
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/cpu0/topology/core_cpus
firefox.desktop[1910918]: [1910918] Sandbox: attempt to open unexpected file /sys/devices/system/cpu/cpu0/topology/thread_siblings
firefox.desktop[1897583]: [Parent 1897583, IPC I/O Parent] WARNING: process 1899313 is a zombie: file /builds/worker/checkouts/gecko/ipc/chromium/src/base/process_util_posix.cc:245
firefox.desktop[1897583]: [Parent 1897583, IPC I/O Parent] WARNING: process 1899879 is a zombie: file /builds/worker/checkouts/gecko/ipc/chromium/src/base/process_util_posix.cc:245
firefox.desktop[1897583]: [Parent 1897583, IPC I/O Parent] WARNING: process 1905217 is a zombie: file /builds/worker/checkouts/gecko/ipc/chromium/src/base/process_util_posix.cc:245
firefox.desktop[1897583]: [Parent 1897583, IPC I/O Parent] WARNING: process 1899310 is a zombie: file /builds/worker/checkouts/gecko/ipc/chromium/src/base/process_util_posix.cc:245
firefox.desktop[1897583]: [Parent 1897583, IPC I/O Parent] WARNING: process 1898347 is a zombie: file /builds/worker/checkouts/gecko/ipc/chromium/src/base/process_util_posix.cc:245
Same issue. Firefox 129.0.1 Ubuntu 24.04 desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/cpu0/ cache/index2/ size desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/cpu0/ cache/index3/ size desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/present desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/possible desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/cpu0/ topology/ core_cpus desktop[ 1910918] : [1910918] Sandbox: attempt to open unexpected file /sys/devices/ system/ cpu/cpu0/ topology/ thread_ siblings desktop[ 1897583] : [Parent 1897583, IPC I/O Parent] WARNING: process 1899313 is a zombie: file /builds/ worker/ checkouts/ gecko/ipc/ chromium/ src/base/ process_ util_posix. cc:245 desktop[ 1897583] : [Parent 1897583, IPC I/O Parent] WARNING: process 1899879 is a zombie: file /builds/ worker/ checkouts/ gecko/ipc/ chromium/ src/base/ process_ util_posix. cc:245 desktop[ 1897583] : [Parent 1897583, IPC I/O Parent] WARNING: process 1905217 is a zombie: file /builds/ worker/ checkouts/ gecko/ipc/ chromium/ src/base/ process_ util_posix. cc:245 desktop[ 1897583] : [Parent 1897583, IPC I/O Parent] WARNING: process 1899310 is a zombie: file /builds/ worker/ checkouts/ gecko/ipc/ chromium/ src/base/ process_ util_posix. cc:245 desktop[ 1897583] : [Parent 1897583, IPC I/O Parent] WARNING: process 1898347 is a zombie: file /builds/ worker/ checkouts/ gecko/ipc/ chromium/ src/base/ process_ util_posix. cc:245
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