platform/x86: dell-wmi-sysman: Fix instance ID bounds

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The get_instance_id() macro walks the per-type attribute array with
'i <= instances_count'.  Each array is allocated with exactly
instances_count entries, so the valid range is [0, instances_count)
and the last iteration reads one element past the end.  On a name miss
that out-of-bounds attribute_name is handed to strcmp(), which reads on
until it finds a NUL byte.

Every kobject in these ksets is built from an entry that was populated,
so a miss does not look reachable from sysfs today.  The bound is wrong
either way and the read is out of bounds.

The matching macro in hp-bioscfg carried the same off-by-one and was
corrected by commit 25150715e0 ("platform/x86: hp-bioscfg: Fix kernel
panic in GET_INSTANCE_ID macro").  That macro takes a kobject pointer
out of the out-of-bounds element and dereferences it, so it could fault.
This one reads a char array.

Use '<' to match the allocation.

Fixes: e8a60aa740 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Assisted-by: Claude:claude-opus-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
Link: https://patch.msgid.link/20260814132535.4169956-1-sammiee5311@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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HyeongJun An 2026-08-14 22:25:35 +09:00 • committed by Ilpo Järvinen

parent 28e5e68259

commit 5ab078e324

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drivers/platform/x86/dell/dell-wmi-sysman/dell-wmi-sysman.h

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