linux/tools
Changbin Du bbf8c67aa6 tools: jobserver: Prevent deadlock caused by incorrect jobserver configuration and enhance error reporting
When using GNU Make's jobserver feature in kernel builds, a bug in MAKEFLAGS
propagation caused "--jobserver-auth=r,w" to reference an unintended file
descriptor. This led to infinite loops in jobserver-exec's os.read() calls
due to empty token.

My shell opened /etc/passwd for some reason without closing it, and as a
result, all child processes inherited this fd 3.

$ ls -l /proc/self/fd
total 0
lrwx------ 1 changbin changbin 64 Dec 25 13:03 0 -> /dev/pts/1
lrwx------ 1 changbin changbin 64 Dec 25 13:03 1 -> /dev/pts/1
lrwx------ 1 changbin changbin 64 Dec 25 13:03 2 -> /dev/pts/1
lr-x------ 1 changbin changbin 64 Dec 25 13:03 3 -> /etc/passwd
lr-x------ 1 changbin changbin 64 Dec 25 13:03 4 -> /proc/1421383/fd

In this case, the `make` should open a new file descriptor for jobserver
control, but clearly, it did not do so and instead still passed fd 3 as
"--jobserver-auth=3,4" in MAKEFLAGS. (The version of my gnu make is 4.3)

This update ensures robustness against invalid jobserver configurations,
even when `make` incorrectly pass non-pipe file descriptors.
 * Rejecting empty reads to prevent infinite loops on EOF.
 * Clearing `self.jobs` to avoid writing to incorrect files if invalid tokens
   are detected.
 * Printing detailed error messages to stderr to inform the user.

Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Changbin Du <changbin.du@huawei.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260108113836.2976527-1-changbin.du@huawei.com>
2026-01-12 08:45:38 -07:00
..
accounting tools/delaytop: improve error handling for missing PSI support 2025-09-13 17:32:56 -07:00
arch [GIT PULL] perf tools changes for v6.19 2025-12-07 07:07:02 -08:00
bootconfig
bpf bpftool: Fix build warnings due to MS extensions 2025-12-09 23:21:33 -08:00
build [GIT PULL] perf tools changes for v6.19 2025-12-07 07:07:02 -08:00
certs
cgroup
counter
crypto
debugging
dma dma-mapping updates for Linux 6.19: 2025-12-06 09:25:05 -08:00
docs docs: find-unused-docs.sh: fixup directory usage 2026-01-06 14:36:07 -07:00
firewire
firmware
gpio tools: gpio: remove the include directory on make clean 2025-09-04 16:29:28 +02:00
hv
iio iio: add power and energy measurement modifiers 2025-09-13 13:47:19 +01:00
include hyperv-next for v6.19 2025-12-09 06:10:17 +09:00
kvm/kvm_stat
laptop
leds
lib tools: jobserver: Prevent deadlock caused by incorrect jobserver configuration and enhance error reporting 2026-01-12 08:45:38 -07:00
memory-model
mm tools/mm/page_owner_sort: add help option support 2025-11-16 17:28:06 -08:00
net Including fixes from netfilter and CAN. 2025-12-19 07:55:35 +12:00
objtool objtool: Add more robust signal error handling, detect and warn about stack overflows 2025-12-03 19:42:37 +01:00
pcmcia
perf [GIT PULL] perf tools changes for v6.19 2025-12-07 07:07:02 -08:00
power platform-drivers-x86 for v6.19-1 2025-12-10 06:38:17 +09:00
rcu
sched
sched_ext sched_ext: tools: Removing duplicate targets during non-cross compilation 2025-11-20 07:00:27 -10:00
scripts
sound
spi
testing Two left-over updates that could not go into -rc1 due to conflicts with 2025-12-20 11:34:37 -08:00
thermal tools/thermal/thermal-engine: Fix format string bug in thermal-engine 2025-11-25 11:00:28 +01:00
time
tracing rtla updaets for v6.19: 2025-12-05 09:34:01 -08:00
usb tools/usb/usbip: fix spelling mistakes in usbipd.c 2025-09-06 15:22:14 +02:00
verification
virtio tools/virtio: replace "__auto_type" with "auto" 2025-12-08 15:32:15 -08:00
wmi
workqueue
writeback
Makefile tools/dma: move dma_map_benchmark from selftests to tools/dma 2025-10-29 09:41:40 +01:00