linux/drivers
Sergey Senozhatsky 0be909f114 zsmalloc: use actual object size to detect spans
Using class->size to detect spanning objects is not entirely correct,
because some size classes can hold a range of object sizes of up to
class->size bytes in length, due to size-classes merge.  Such classes use
padding for cases when actually written objects are smaller than
class->size.  zs_obj_read_begin() can incorrectly hit the slow path and
perform memcpy of such objects, basically copying padding bytes.  Instead
of class->size zs_obj_read_begin() should use the actual compressed object
length (both zram and zswap know it) so that it can correctly handle
situations when a written object is small enough to fit into the first
physical page.

Link: https://lkml.kernel.org/r/20260107052145.3586917-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>	[zsmalloc & zswap]
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 20:02:25 -08:00
..
accel
accessibility
acpi
amba
android
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atm
auxdisplay
base
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block zsmalloc: use actual object size to detect spans 2026-01-26 20:02:25 -08:00
bluetooth
bus
cache
cdrom
cdx
char
clk
clocksource
comedi
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counter
cpufreq
cpuidle
crypto
cxl
dax
dca
devfreq
dibs
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dpll
edac
eisa
extcon
firewire
firmware
fpga
fsi
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gnss
gpib
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hte
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