On 2023/8/8 11:17, Shuai Xue wrote:
>
>
> On 2023/7/10 11:15, Shuai Xue wrote:
>>
>>
>> On 2023/6/16 15:15, Shuai Xue wrote:
>>>
>>>
>>> On 2023/6/6 15:42, Shuai Xue wrote:
>>>> changes since v6:
>>>> - add more explicty error message suggested by Xiaofei
>>>> - pick up reviewed-by tag from Xiaofei
>>>> - pick up internal reviewed-by tag from Baolin
>>>>
>>>> changes since v5 by addressing comments from Kefeng:
>>>> - document return value of memory_failure()
>>>> - drop redundant comments in call site of memory_failure()
>>>> - make ghes_do_proc void and handle abnormal case within it
>>>> - pick up reviewed-by tag from Kefeng Wang
>>>>
>>>> changes since v4 by addressing comments from Xiaofei:
>>>> - do a force kill only for abnormal sync errors
>>>>
>>>> changes since v3 by addressing comments from Xiaofei:
>>>> - do a force kill for abnormal memory failure error such as invalid PA,
>>>> unexpected severity, OOM, etc
>>>> - pcik up tested-by tag from Ma Wupeng
>>>>
>>>> changes since v2 by addressing comments from Naoya:
>>>> - rename mce_task_work to sync_task_work
>>>> - drop ACPI_HEST_NOTIFY_MCE case in is_hest_sync_notify()
>>>> - add steps to reproduce this problem in cover letter
>>>>
>>>> changes since v1:
>>>> - synchronous events by notify type
>>>> - Link: https://lore.kernel.org/lkml/20221206153354.92394-3-xueshuai@linux.alibaba.…
>>>>
>>>>
>>>> Shuai Xue (2):
>>>> ACPI: APEI: set memory failure flags as MF_ACTION_REQUIRED on
>>>> synchronous events
>>>> ACPI: APEI: handle synchronous exceptions in task work
>>>>
>>>> arch/x86/kernel/cpu/mce/core.c | 9 +--
>>>> drivers/acpi/apei/ghes.c | 113 ++++++++++++++++++++++-----------
>>>> include/acpi/ghes.h | 3 -
>>>> mm/memory-failure.c | 17 +----
>>>> 4 files changed, 79 insertions(+), 63 deletions(-)
>>>>
>>>
>>>
>>> Hi, Rafael,
>>>
>>> Gentle ping.
>>>
>>> Are you happy to queue this patch set or anything I can do to improve it?
>>> As @Kefeng said, this issue is met in Alibaba and Huawei products, we hope it
>>> could be fixed ASAP.
>>
>> Hi Rafael, Tony, and Naoya,
>>
>> Gentle ping. I am sorry to see that we have missed v6.3 and v6.4 merge window
>> since three Reviewed-by tags and one Tested-by tag.
>>
>> Do we still need any designated APEI reviewers Reviewed-by? Could you give me your
>> Reviewed-by @Tony, and @Naoya if you are happy with the change.
>>
>> Or Please could you Ack this change if you are happy with the proposal and the
>> change? @Rafael
>>
>
> Hi, ALL,
>
> Gentle ping.
>
Hi, ALL,
I have rewritten the cover letter with the hope that the maintainer will truly
understand the necessity of this patch. Both Alibaba and Huawei met the same
issue in products, and we hope it could be fixed ASAP.
There are two major types of uncorrected recoverable (UCR) errors :
- Action Required (AR): The error is detected and the processor already
consumes the memory. OS requires to take action (for example, offline
failure page/kill failure thread) to recover this error.
- Action Optional (AO): The error is detected out of processor execution
context. Some data in the memory are corrupted. But the data have not
been consumed. OS is optional to take action to recover this error.
The main difference between AR and AO errors is that AR errors are synchronous
events, while AO errors are asynchronous events. Synchronous exceptions, such as
Machine Check Exception (MCE) on X86 and Synchronous External Abort (SEA) on
Arm64, are signaled by the hardware when an error is detected and the memory
access has architecturally been executed.
Currently, both synchronous and asynchronous errors are queued as AO errors and
handled by a dedicated kernel thread in a work queue on the ARM64 platform. For
synchronous errors, memory_failure() is synced using a cancel_work_sync trick to
ensure that the corrupted page is unmapped and poisoned. Upon returning to
user-space, the process resumes at the current instruction, triggering a page
fault. As a result, the kernel sends a SIGBUS signal to the current process due
to VM_FAULT_HWPOISON.
However, this trick is not always be effective, this patch set improves the
recovery process in three specific aspects:
1. Handle synchronous exceptions with proper si_code
ghes_handle_memory_failure() queue both synchronous and asynchronous errors with
flag=0. Then the kernel will notify the process by sending a SIGBUS signal in
memory_failure() with wrong si_code: BUS_MCEERR_AO to the actual user-space
process instead of BUS_MCEERR_AR. The user-space processes rely on the si_code
to distinguish to handle memory failure.
For example, hwpoison-aware user-space processes use the si_code: BUS_MCEERR_AO
for 'action optional' early notifications, and BUS_MCEERR_AR for 'action
required' synchronous/late notifications. Specifically, when a SIGBUS_MCEERR_AR
synchronous signal is delivered to QEMU, it will inject a vSEA to Guest
kernel.[1]
Fix it by seting memory failure flags as MF_ACTION_REQUIRED on synchronous events. (PATCH 1)
2. Handle memory_failure() abnormal fails to avoid a unnecessary reboot
If process mapping fault page, but memory_failure() abnormal return before
try_to_unmap(), for example, the fault page process mapping is KSM page.
In this case, arm64 cannot use the page fault process to terminate the
synchronous exception loop.
This loop can potentially exceed the platform firmware threshold or even trigger
a kernel hard lockup, leading to a system reboot. However, kernel has the
capability to recover from this error.
Fix it by performing a force kill when memory_failure() abnormal fails or when
other abnormal synchronous errors occur. These errors can include situations
such as invalid PA, unexpected severity, no memory failure config support,
invalid GUID section, OOM, etc. (PATCH 2)
3. Handle memory_failure() in current process context which consuming poison
When synchronous errors occur, memory_failure() assume that current process
context is exactly that consuming poison synchronous error.
For example, kill_accessing_process() holds mmap locking of current->mm, does
pagetable walk to find the error virtual address, and sends SIGBUS to the
current process with error info. However, the mm of kworker is not valid,
resulting in a null-pointer dereference. I have fixed this in[3].
commit 77677cdbc2aa mm,hwpoison: check mm when killing accessing process
Another example is that collect_procs()/kill_procs() walk the task list, only
collect and send sigbus to task which consuming poison. But memory_failure() is
queued and handled by a dedicated kernel thread on arm64 platform.
Fix it by queuing memory_failure() as a task work which runs in current
execution context to synchronously send SIGBUS before ret_to_user. (PATCH 2)
Lv Ying and XiuQi from Huawei also proposed to address similar problem[2][4].
Acknowledge to discussion with them.
To reproduce this problem:
# STEP1: enable early kill mode
#sysctl -w vm.memory_failure_early_kill=1
vm.memory_failure_early_kill = 1
# STEP2: inject an UCE error and consume it to trigger a synchronous error
#einj_mem_uc single
0: single vaddr = 0xffffb0d75400 paddr = 4092d55b400
injecting ...
triggering ...
signal 7 code 5 addr 0xffffb0d75000
page not present
Test passed
The si_code (code 5) from einj_mem_uc indicates that it is BUS_MCEERR_AO error
and it is not fact.
After this patch set:
# STEP1: enable early kill mode
#sysctl -w vm.memory_failure_early_kill=1
vm.memory_failure_early_kill = 1
# STEP2: inject an UCE error and consume it to trigger a synchronous error
#einj_mem_uc single
0: single vaddr = 0xffffb0d75400 paddr = 4092d55b400
injecting ...
triggering ...
signal 7 code 4 addr 0xffffb0d75000
page not present
Test passed
The si_code (code 4) from einj_mem_uc indicates that it is BUS_MCEERR_AR error
as we expected.
[1] Add ARMv8 RAS virtualization support in QEMU https://patchew.org/QEMU/20200512030609.19593-1-gengdongjiu@huawei.com/
[2] https://lore.kernel.org/lkml/20221205115111.131568-3-lvying6@huawei.com/
[3] https://lkml.kernel.org/r/20220914064935.7851-1-xueshuai@linux.alibaba.com
[4] https://lore.kernel.org/lkml/20221209095407.383211-1-lvying6@huawei.com/
stable-rc/linux-5.4.y build: 17 builds: 0 failed, 17 passed, 34 warnings (v5.4.256-240-ga44590c54f02)
Full Build Summary: https://kernelci.org/build/stable-rc/branch/linux-5.4.y/kernel/v5.4.256-240…
Tree: stable-rc
Branch: linux-5.4.y
Git Describe: v5.4.256-240-ga44590c54f02
Git Commit: a44590c54f0290f6978aed83db34dee74728f9c4
Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
Built: 7 unique architectures
Warnings Detected:
arc:
arm64:
defconfig (gcc-10): 3 warnings
defconfig+arm64-chromebook (gcc-10): 4 warnings
arm:
imx_v6_v7_defconfig (gcc-10): 1 warning
omap2plus_defconfig (gcc-10): 1 warning
i386:
allnoconfig (gcc-10): 2 warnings
i386_defconfig (gcc-10): 3 warnings
tinyconfig (gcc-10): 2 warnings
mips:
riscv:
x86_64:
allnoconfig (gcc-10): 4 warnings
tinyconfig (gcc-10): 4 warnings
x86_64_defconfig (gcc-10): 5 warnings
x86_64_defconfig+x86-chromebook (gcc-10): 5 warnings
Warnings summary:
7 ld: warning: creating DT_TEXTREL in a PIE
7 fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
4 ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
4 arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
3 ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text'
2 arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.
2 arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call
2 arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call
2 arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret'
1 drivers/gpu/drm/mediatek/mtk_drm_gem.c:273:10: warning: returning ‘int’ from a function with return type ‘void *’ makes pointer from integer without a cast [-Wint-conversion]
Section mismatches summary:
1 WARNING: vmlinux.o(___ksymtab_gpl+vic_init_cascaded+0x0): Section mismatch in reference from the variable __ksymtab_vic_init_cascaded to the function .init.text:vic_init_cascaded()
================================================================================
Detailed per-defconfig build reports:
--------------------------------------------------------------------------------
32r2el_defconfig (mips, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
--------------------------------------------------------------------------------
allnoconfig (i386, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches
Warnings:
ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
allnoconfig (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches
Warnings:
arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret'
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call
ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
defconfig (riscv, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
--------------------------------------------------------------------------------
defconfig (arm64, gcc-10) — PASS, 0 errors, 3 warnings, 0 section mismatches
Warnings:
arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
--------------------------------------------------------------------------------
defconfig+arm64-chromebook (arm64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches
Warnings:
arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
drivers/gpu/drm/mediatek/mtk_drm_gem.c:273:10: warning: returning ‘int’ from a function with return type ‘void *’ makes pointer from integer without a cast [-Wint-conversion]
--------------------------------------------------------------------------------
haps_hs_smp_defconfig (arc, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
--------------------------------------------------------------------------------
i386_defconfig (i386, gcc-10) — PASS, 0 errors, 3 warnings, 0 section mismatches
Warnings:
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
imx_v6_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 1 warning, 0 section mismatches
Warnings:
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
--------------------------------------------------------------------------------
multi_v5_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
Section mismatches:
WARNING: vmlinux.o(___ksymtab_gpl+vic_init_cascaded+0x0): Section mismatch in reference from the variable __ksymtab_vic_init_cascaded to the function .init.text:vic_init_cascaded()
--------------------------------------------------------------------------------
multi_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
--------------------------------------------------------------------------------
omap2plus_defconfig (arm, gcc-10) — PASS, 0 errors, 1 warning, 0 section mismatches
Warnings:
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
--------------------------------------------------------------------------------
tinyconfig (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches
Warnings:
arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret'
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call
ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
tinyconfig (i386, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches
Warnings:
ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
vexpress_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches
--------------------------------------------------------------------------------
x86_64_defconfig (x86_64, gcc-10) — PASS, 0 errors, 5 warnings, 0 section mismatches
Warnings:
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call
arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
--------------------------------------------------------------------------------
x86_64_defconfig+x86-chromebook (x86_64, gcc-10) — PASS, 0 errors, 5 warnings, 0 section mismatches
Warnings:
arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call
arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.
fs/quota/dquot.c:2611:1: warning: label ‘out’ defined but not used [-Wunused-label]
ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
ld: warning: creating DT_TEXTREL in a PIE
---
For more info write to <info(a)kernelci.org>
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 65e710899fd19f435f40268f3a92dfaa11f14470
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023091034-applaud-urologist-8167@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 65e710899fd19f435f40268f3a92dfaa11f14470 Mon Sep 17 00:00:00 2001
From: Song Liu <song(a)kernel.org>
Date: Wed, 6 Sep 2023 10:52:15 -0700
Subject: [PATCH] x86/build: Fix linker fill bytes quirk/incompatibility for
ld.lld
With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000.
Example objdump -D output:
ffffffff82b04203: 00 00 add %al,(%rax)
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: 00 00 add %al,(%rax)
ffffffff82b04209: cc int3
ffffffff82b0420a: cc int3
Replace it with ":text =0xcccccccc", so we get the following instead:
ffffffff82b04203: cc int3
ffffffff82b04204: cc int3
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: cc int3
ffffffff82b04208: cc int3
gcc/ld doesn't seem to have the same issue. The generated code stays the
same for gcc/ld.
Signed-off-by: Song Liu <song(a)kernel.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 83d41c2601d7..f15fb71f280e 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -156,7 +156,7 @@ SECTIONS
ALIGN_ENTRY_TEXT_END
*(.gnu.warning)
- } :text =0xcccc
+ } :text = 0xcccccccc
/* End of text section, which should occupy whole number of pages */
_etext = .;
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 65e710899fd19f435f40268f3a92dfaa11f14470
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023091033-scone-precinct-e841@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 65e710899fd19f435f40268f3a92dfaa11f14470 Mon Sep 17 00:00:00 2001
From: Song Liu <song(a)kernel.org>
Date: Wed, 6 Sep 2023 10:52:15 -0700
Subject: [PATCH] x86/build: Fix linker fill bytes quirk/incompatibility for
ld.lld
With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000.
Example objdump -D output:
ffffffff82b04203: 00 00 add %al,(%rax)
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: 00 00 add %al,(%rax)
ffffffff82b04209: cc int3
ffffffff82b0420a: cc int3
Replace it with ":text =0xcccccccc", so we get the following instead:
ffffffff82b04203: cc int3
ffffffff82b04204: cc int3
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: cc int3
ffffffff82b04208: cc int3
gcc/ld doesn't seem to have the same issue. The generated code stays the
same for gcc/ld.
Signed-off-by: Song Liu <song(a)kernel.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 83d41c2601d7..f15fb71f280e 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -156,7 +156,7 @@ SECTIONS
ALIGN_ENTRY_TEXT_END
*(.gnu.warning)
- } :text =0xcccc
+ } :text = 0xcccccccc
/* End of text section, which should occupy whole number of pages */
_etext = .;
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 65e710899fd19f435f40268f3a92dfaa11f14470
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023091031-reapply-headed-88ad@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 65e710899fd19f435f40268f3a92dfaa11f14470 Mon Sep 17 00:00:00 2001
From: Song Liu <song(a)kernel.org>
Date: Wed, 6 Sep 2023 10:52:15 -0700
Subject: [PATCH] x86/build: Fix linker fill bytes quirk/incompatibility for
ld.lld
With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000.
Example objdump -D output:
ffffffff82b04203: 00 00 add %al,(%rax)
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: 00 00 add %al,(%rax)
ffffffff82b04209: cc int3
ffffffff82b0420a: cc int3
Replace it with ":text =0xcccccccc", so we get the following instead:
ffffffff82b04203: cc int3
ffffffff82b04204: cc int3
ffffffff82b04205: cc int3
ffffffff82b04206: cc int3
ffffffff82b04207: cc int3
ffffffff82b04208: cc int3
gcc/ld doesn't seem to have the same issue. The generated code stays the
same for gcc/ld.
Signed-off-by: Song Liu <song(a)kernel.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 83d41c2601d7..f15fb71f280e 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -156,7 +156,7 @@ SECTIONS
ALIGN_ENTRY_TEXT_END
*(.gnu.warning)
- } :text =0xcccc
+ } :text = 0xcccccccc
/* End of text section, which should occupy whole number of pages */
_etext = .;