| Message ID | 20240401102511.495791-1-ynezz@true.cz |
|---|---|
| State | Under Review |
| Delegated to: | Petr Štetiar |
| Headers | show |
| Series | image.mk: fix dd memory exhaustion during padding of large images | expand |
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On Mon, Apr 01, 2024 at 10:25:11AM +0000, Petr Štetiar wrote:
> + bs=1048576 count=$(shell expr $(2) / 1048576) \
How about using dd iflag=count_bytes instead?
OpenWrt's busybox supports it.
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On Mon, Apr 01, 2024 at 03:34:09PM +0200, Mirko Parthey wrote:
> OpenWrt's busybox supports it.
Please disregard this, support is required on the build host.
diff --git a/include/image.mk b/include/image.mk index 4b6acbe1aad6..2586f29160f6 100644 --- a/include/image.mk +++ b/include/image.mk @@ -163,7 +163,13 @@ DTC_FLAGS += $(DTC_WARN_FLAGS) DTCO_FLAGS += $(DTC_WARN_FLAGS) define Image/pad-to - dd if=$(1) of=$(1).new bs=$(2) conv=sync + if [ $(2) -gt 1048576 ]; then \ + dd if=$(1) of=$(1).new \ + bs=1048576 count=$(shell expr $(2) / 1048576) \ + conv=sync ; \ + else \ + dd if=$(1) of=$(1).new bs=$(2) conv=sync ; \ + fi mv $(1).new $(1) endef
This commit adjusts the Image/pad-to function within image.mk to improve memory management when padding large images. Previously, the dd command was used with a block size (bs) directly derived from the target padding size. This could lead to inefficiencies or memory exhaustion issues when dealing with very large images. To address this, a conditional has been introduced: If the desired padding size exceeds 1MiB (1048576 bytes), dd now operates with a block size of 1MiB and calculates the necessary count to achieve the desired padding. This approach aims to balance memory usage and performance by avoiding excessively large block sizes in memory-intensive operations. For padding sizes of 1MiB or less, the original behavior is preserved, using the specified padding size as the block size. This change ensures more reliable and efficient image padding, particularly in environments with limited memory resources. References: https://github.com/openwrt/openwrt/pull/2862 Reported-by: Nishant Sharma <codemarauder@gmail.com> Suggested-by: shir474 <shir474@users.noreply.github.com> Signed-off-by: Petr Štetiar <ynezz@true.cz> --- include/image.mk | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)