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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Matthias Maennich <maennich@google.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 06/47] kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
Date: Mon, 26 Jul 2021 17:38:24 +0200	[thread overview]
Message-ID: <20210726153823.182910659@linuxfoundation.org> (raw)
In-Reply-To: <20210726153822.980271128@linuxfoundation.org>

From: Matthias Maennich <maennich@google.com>

[ Upstream commit a979522a1a88556e42a22ce61bccc58e304cb361 ]

To avoid unnecessary recompilations, mkcompile_h does not regenerate
compile.h if just the timestamp changed.
Though, if KBUILD_BUILD_TIMESTAMP is set, an explicit timestamp for the
build was requested, in which case we should not ignore it.

If a user follows the documentation for reproducible builds [1] and
defines KBUILD_BUILD_TIMESTAMP as the git commit timestamp, a clean
build will have the correct timestamp. A subsequent cherry-pick (or
amend) changes the commit timestamp and if an incremental build is done
with a different KBUILD_BUILD_TIMESTAMP now, that new value is not taken
into consideration. But it should for reproducibility.

Hence, whenever KBUILD_BUILD_TIMESTAMP is explicitly set, do not ignore
UTS_VERSION when making a decision about whether the regenerated version
of compile.h should be moved into place.

[1] https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html

Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/mkcompile_h | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index 6fdc97ef6023..cb73747002ed 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -82,15 +82,23 @@ UTS_TRUNCATE="cut -b -$UTS_LEN"
 # Only replace the real compile.h if the new one is different,
 # in order to preserve the timestamp and avoid unnecessary
 # recompilations.
-# We don't consider the file changed if only the date/time changed.
+# We don't consider the file changed if only the date/time changed,
+# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
+# reproducible builds with that value referring to a commit timestamp).
 # A kernel config change will increase the generation number, thus
 # causing compile.h to be updated (including date/time) due to the
 # changed comment in the
 # first line.
 
+if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
+   IGNORE_PATTERN="UTS_VERSION"
+else
+   IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
+fi
+
 if [ -r $TARGET ] && \
-      grep -v 'UTS_VERSION' $TARGET > .tmpver.1 && \
-      grep -v 'UTS_VERSION' .tmpcompile > .tmpver.2 && \
+      grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
+      grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
       cmp -s .tmpver.1 .tmpver.2; then
    rm -f .tmpcompile
 else
-- 
2.30.2




  parent reply	other threads:[~2021-07-26 15:41 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 15:38 [PATCH 4.4 00/47] 4.4.277-rc1 review Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 01/47] ARM: brcmstb: dts: fix NAND nodes names Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 02/47] ARM: dts: BCM63xx: Fix " Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 03/47] ARM: dts: imx6: phyFLEX: Fix UART hardware flow control Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 04/47] ARM: imx: pm-imx5: Fix references to imx5_cpu_suspend_info Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 05/47] thermal/core: Correct function name thermal_zone_device_unregister() Greg Kroah-Hartman
2021-07-26 15:38 ` Greg Kroah-Hartman [this message]
2021-07-26 15:38 ` [PATCH 4.4 07/47] scsi: aic7xxx: Fix unintentional sign extension issue on left shift of u8 Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 08/47] sched/fair: Fix CFS bandwidth hrtimer expiry type Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 09/47] Revert "memory: fsl_ifc: fix leak of IO mapping on probe failure" Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 10/47] x86/fpu: Make init_fpstate correct with optimized XSAVE Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 11/47] net: ipv6: fix return value of ip6_skb_dst_mtu Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 12/47] net: bcmgenet: Ensure all TX/RX queues DMAs are disabled Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 13/47] net: moxa: fix UAF in moxart_mac_probe Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 14/47] net: ti: fix UAF in tlan_remove_one Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 15/47] net: validate lwtstate->data before returning from skb_tunnel_info() Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 16/47] tcp: annotate data races around tp->mtu_info Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 17/47] ipv6: tcp: drop silly ICMPv6 packet too big messages Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 18/47] iavf: Fix an error handling path in iavf_probe() Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 19/47] igb: Check if num of q_vectors is smaller than max before array access Greg Kroah-Hartman
2021-07-26 21:57   ` Pavel Machek
2021-07-26 15:38 ` [PATCH 4.4 20/47] perf test session_topology: Delete session->evlist Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 21/47] perf test bpf: Free obj_buf Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 22/47] perf probe-file: Delete namelist in del_events() on the error path Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 23/47] s390/bpf: Perform r1 range checking before accessing jit->seen_reg[r1] Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 24/47] net: fix uninit-value in caif_seqpkt_sendmsg Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 25/47] net: decnet: Fix sleeping inside in af_decnet Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 26/47] netrom: Decrease sock refcount when sock timers expire Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 27/47] scsi: iscsi: Fix iface sysfs attr detection Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 28/47] scsi: target: Fix protect handling in WRITE SAME(32) Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 29/47] Revert "USB: quirks: ignore remote wake-up on Fibocom L850-GL LTE modem" Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 30/47] proc: Avoid mixing integer types in mem_rw() Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 31/47] s390/ftrace: fix ftrace_update_ftrace_func implementation Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 32/47] ALSA: sb: Fix potential ABBA deadlock in CSP driver Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 33/47] xhci: Fix lost USB 2 remote wake Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 34/47] KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 35/47] usb: hub: Disable USB 3 device initiated lpm if exit latency is too high Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 36/47] USB: usb-storage: Add LaCie Rugged USB3-FW to IGNORE_UAS Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 37/47] usb: max-3421: Prevent corruption of freed memory Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 38/47] usb: renesas_usbhs: Fix superfluous irqs happen after usb_pkt_pop() Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 39/47] USB: serial: option: add support for u-blox LARA-R6 family Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 40/47] USB: serial: cp210x: fix comments for GE CS1000 Greg Kroah-Hartman
2021-07-26 15:38 ` [PATCH 4.4 41/47] USB: serial: cp210x: add ID for CEL EM3588 USB ZigBee stick Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 42/47] tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 43/47] media: ngene: Fix out-of-bounds bug in ngene_command_config_free_buf() Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 44/47] net: bcmgenet: ensure EXT_ENERGY_DET_MASK is clear Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 45/47] iio: accel: bma180: Use explicit member assignment Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 46/47] iio: accel: bma180: Fix BMA25x bandwidth register values Greg Kroah-Hartman
2021-07-26 15:39 ` [PATCH 4.4 47/47] btrfs: compression: dont try to compress if we dont have enough pages Greg Kroah-Hartman
2021-07-27  0:37 ` [PATCH 4.4 00/47] 4.4.277-rc1 review Shuah Khan
2021-07-27  3:49 ` Naresh Kamboju

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