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07be53cfa8
bash and dash evaluate variables differently.
dash will evaluate '\\' every time it is read whereas bash does not.
TEST_STRING="$TEST_STRING \\$i"
echo $TEST_STRING
With i=123
On bash, that will print "\123"
but on dash, that will print the escape sequence of \123 as the \ will be
interpreted again in the echo.
The dynevent_limitations.tc test created a very large list of arguments to
test the maximum number of arguments to pass to the dynamic events file.
It had a loop of:
TEST_STRING=$1
# Acceptable
for i in `seq 1 $MAX_ARGS`; do
TEST_STRING="$TEST_STRING \\$i"
done
echo "$TEST_STRING" >> dynamic_events
This worked fine on bash, but when run on dash it failed.
This was due to dash interpreting the "\\$i" twice. Once when it was
assigned to TEST_STRING and a second time with the echo $TEST_STRING.
bash does not process the backslash more than the first time.
To solve this, assign a double backslash to a variable "bs" and then echo
it to "ts". If "ts" changes, it is dash, if not, it is bash. Then update
"bs" accordingly, and use that to assign TEST_STRING.
Now this could possibly just check if "$BASH" is defined or not, but this
is testing if the issue exists and not just which shell is being used.
Link: https://lore.kernel.org/r/20250414210900.4de5e8b9@gandalf.local.home
Fixes:
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|---|---|---|
| .. | ||
| accounting | ||
| arch | ||
| bootconfig | ||
| bpf | ||
| build | ||
| certs | ||
| cgroup | ||
| counter | ||
| crypto | ||
| debugging | ||
| firewire | ||
| firmware | ||
| gpio | ||
| hv | ||
| iio | ||
| include | ||
| kvm/kvm_stat | ||
| laptop | ||
| leds | ||
| lib | ||
| memory-model | ||
| mm | ||
| net | ||
| objtool | ||
| pcmcia | ||
| perf | ||
| power | ||
| rcu | ||
| sched_ext | ||
| scripts | ||
| sound | ||
| spi | ||
| testing | ||
| thermal | ||
| time | ||
| tracing | ||
| usb | ||
| verification | ||
| virtio | ||
| wmi | ||
| workqueue | ||
| writeback | ||
| Makefile | ||