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[PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover

Alice Ryhl posted 2 patches 1 week, 1 day ago
[PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Alice Ryhl 1 week, 1 day ago 
We do not pass -fsanitize-recover to clang, so for consistency we should
not pass -Zsanitizer-recover to rustc. Thus, remove these flags.

Fixes: e3117404b411 ("kbuild: rust: Enable KASAN support")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 scripts/Makefile.kasan | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 0ba2aac3b8dc..9a9033096c88 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -49,7 +49,6 @@ CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
 # The minimum supported `rustc` version has a minimum supported LLVM
 # version late enough that we can assume support for -asan-mapping-offset.
 RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \
-		   -Zsanitizer-recover=kernel-address \
 		   -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET)
 
 # Now, add other parameters enabled similarly in GCC, Clang, and rustc.
@@ -73,8 +72,7 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress
 
 # This sets flags that will enable SW_TAGS KASAN once enabled in Rust. These
 # will not work today, and is guarded against in dependencies for CONFIG_RUST.
-RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \
-		   -Zsanitizer-recover=kernel-hwaddress
+RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress
 
 ifdef CONFIG_KASAN_INLINE
 	kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)

-- 
2.53.0.1018.g2bb0e51243-goog
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by kernel test robot 6 days, 11 hours ago 
Hi Alice,

kernel test robot noticed the following build errors:

[auto build test ERROR on 1f318b96cc84d7c2ab792fcc0bfd42a7ca890681]

url:    https://github.com/intel-lab-lkp/linux/commits/Alice-Ryhl/rust-kasan-do-not-pass-Zsanitizer-recover/20260326-213339
base:   1f318b96cc84d7c2ab792fcc0bfd42a7ca890681
patch link:    https://lore.kernel.org/r/20260325-kasan-rust-sw-tags-v1-1-7d3a765a72aa%40google.com
patch subject: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
config: x86_64-randconfig-071-20260327 (https://download.01.org/0day-ci/archive/20260327/202603271853.RhfDTdOp-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260327/202603271853.RhfDTdOp-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202603271853.RhfDTdOp-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld.lld: error: undefined symbol: __asan_report_load8
   >>> referenced by kvec.rs:847 (rust/kernel/alloc/kvec.rs:847)
   >>>               samples/rust/rust_soc.o:(core::ptr::drop_in_place::<kernel::str::CString>) in archive vmlinux.a
   >>> referenced by kvec.rs:847 (rust/kernel/alloc/kvec.rs:847)
   >>>               samples/rust/rust_soc.o:(core::ptr::drop_in_place::<kernel::str::CString>) in archive vmlinux.a
   >>> referenced by aref.rs:170 (rust/kernel/sync/aref.rs:170)
   >>>               samples/rust/rust_soc.o:(<kernel::driver::Registration<kernel::platform::Adapter<rust_soc::SampleSocDriver>>>::post_unbind_callback) in archive vmlinux.a
   >>> referenced 3034 more times
--
>> ld.lld: error: undefined symbol: __asan_report_store8
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
   >>>               samples/rust/rust_soc.o:(<kernel::platform::Adapter<rust_soc::SampleSocDriver>>::probe_callback) in archive vmlinux.a
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
   >>>               samples/rust/rust_soc.o:(<kernel::platform::Adapter<rust_soc::SampleSocDriver>>::probe_callback) in archive vmlinux.a
   >>> referenced by rust_configfs.rs:86 (samples/rust/rust_configfs.rs:86)
   >>>               samples/rust/rust_configfs.o:(<rust_configfs::Configuration as kernel::configfs::GroupOperations>::make_group) in archive vmlinux.a
   >>> referenced 1783 more times
--
>> ld.lld: error: undefined symbol: __asan_report_load16
   >>> referenced by num.rs:648 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/fmt/num.rs:648)
   >>>               rust/core.o:(<u128 as core::fmt::Display>::fmt) in archive vmlinux.a
   >>> referenced by num.rs:655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/fmt/num.rs:655)
   >>>               rust/core.o:(<i128 as core::fmt::Display>::fmt) in archive vmlinux.a
   >>> referenced by niche_types.rs:100 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/niche_types.rs:100)
   >>>               rust/core.o:(<core::num::niche_types::NonZeroU128Inner as core::fmt::Debug>::fmt) in archive vmlinux.a
   >>> referenced 9 more times
--
>> ld.lld: error: undefined symbol: __asan_report_store16
   >>> referenced by option.rs:1279 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/option.rs:1279)
   >>>               rust/core.o:(<core::num::nonzero::NonZero<u128> as core::str::traits::FromStr>::from_str) in archive vmlinux.a
   >>> referenced by option.rs:1279 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/option.rs:1279)
   >>>               rust/core.o:(<core::num::nonzero::NonZero<i128> as core::str::traits::FromStr>::from_str) in archive vmlinux.a
--
>> ld.lld: error: undefined symbol: __asan_report_load1
   >>> referenced by c_str.rs:416 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ffi/c_str.rs:416)
   >>>               samples/rust/rust_configfs.o:(<kernel::configfs::GroupOperationsVTable<rust_configfs::Configuration, rust_configfs::Child>>::make_group) in archive vmlinux.a
   >>> referenced by c_str.rs:416 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ffi/c_str.rs:416)
   >>>               samples/rust/rust_configfs.o:(<kernel::configfs::GroupOperationsVTable<rust_configfs::Child, rust_configfs::GrandChild>>::make_group) in archive vmlinux.a
   >>> referenced by revocable.rs:218 (rust/kernel/revocable.rs:218)
   >>>               samples/rust/rust_driver_auxiliary.o:(core::ptr::drop_in_place::<kernel::sync::arc::Arc<kernel::revocable::Revocable<kernel::auxiliary::Registration>>>) in archive vmlinux.a
   >>> referenced 890 more times
--
>> ld.lld: error: undefined symbol: __asan_report_store4
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
   >>>               samples/rust/rust_configfs.o:(<kernel::configfs::GroupOperationsVTable<rust_configfs::Configuration, rust_configfs::Child>>::make_group) in archive vmlinux.a
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
   >>>               samples/rust/rust_configfs.o:(<kernel::configfs::GroupOperationsVTable<rust_configfs::Child, rust_configfs::GrandChild>>::make_group) in archive vmlinux.a
   >>> referenced by result.rs:2050 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/result.rs:2050)
   >>>               samples/rust/rust_configfs.o:(<rust_configfs::Configuration as kernel::configfs::GroupOperations>::make_group) in archive vmlinux.a
   >>> referenced 539 more times
--
>> ld.lld: error: undefined symbol: __asan_report_store1
   >>> referenced by atomic.rs:3845 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:3845)
   >>>               samples/rust/rust_driver_auxiliary.o:(core::ptr::drop_in_place::<kernel::devres::Devres<kernel::auxiliary::Registration>>) in archive vmlinux.a
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
>> >>>               samples/rust/rust_driver_auxiliary.o:(pin_init::pin_init_scope::<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error, <kernel::auxiliary::Registration>::new::{closure#0}, core::result::Result<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error>>::{closure#0}) in archive vmlinux.a
   >>> referenced by atomic.rs:3845 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:3845)
   >>>               samples/rust/rust_driver_pci.o:(core::ptr::drop_in_place::<kernel::devres::Devres<kernel::pci::io::Bar<16>>>) in archive vmlinux.a
   >>> referenced 356 more times
--
>> ld.lld: error: undefined symbol: __asan_report_load4
   >>> referenced by lib.rs:1300 (rust/pin-init/src/lib.rs:1300)
>> >>>               samples/rust/rust_driver_auxiliary.o:(pin_init::pin_init_scope::<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error, <kernel::auxiliary::Registration>::new::{closure#0}, core::result::Result<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error>>::{closure#0}) in archive vmlinux.a
   >>> referenced by io.rs:261 (rust/kernel/pci/io.rs:261)
   >>>               samples/rust/rust_driver_pci.o:(core::ptr::drop_in_place::<kernel::devres::Devres<kernel::pci::io::Bar<16>>>) in archive vmlinux.a
   >>> referenced by io.rs:261 (rust/kernel/pci/io.rs:261)
   >>>               samples/rust/rust_driver_pci.o:(core::ptr::drop_in_place::<kernel::sync::arc::Arc<kernel::revocable::Revocable<kernel::pci::io::Bar<16>>>>) in archive vmlinux.a
   >>> referenced 320 more times
--
>> ld.lld: error: undefined symbol: __asan_report_store_n
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
>> >>>               samples/rust/rust_driver_auxiliary.o:(pin_init::pin_init_scope::<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error, <kernel::auxiliary::Registration>::new::{closure#0}, core::result::Result<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error>>::{closure#0}) in archive vmlinux.a
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
>> >>>               samples/rust/rust_driver_auxiliary.o:(pin_init::pin_init_scope::<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error, <kernel::auxiliary::Registration>::new::{closure#0}, core::result::Result<kernel::devres::Devres<kernel::auxiliary::Registration>, kernel::error::Error>>::{closure#0}) in archive vmlinux.a
   >>> referenced by mod.rs:1655 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ptr/mod.rs:1655)
   >>>               samples/rust/rust_driver_pci.o:(<kernel::pci::Adapter<rust_driver_pci::SampleDriver>>::probe_callback) in archive vmlinux.a
   >>> referenced 105 more times
--
>> ld.lld: error: undefined symbol: __asan_report_load2
   >>> referenced by pci.rs:372 (rust/kernel/pci.rs:372)
   >>>               samples/rust/rust_driver_pci.o:(<kernel::pci::Adapter<rust_driver_pci::SampleDriver>>::probe_callback) in archive vmlinux.a
   >>> referenced by pci.rs:381 (rust/kernel/pci.rs:381)
   >>>               samples/rust/rust_driver_pci.o:(<kernel::pci::Adapter<rust_driver_pci::SampleDriver>>::probe_callback) in archive vmlinux.a
   >>> referenced by pci.rs:372 (rust/kernel/pci.rs:372)
   >>>               samples/rust/rust_driver_auxiliary.o:(<rust_driver_auxiliary::AuxiliaryDriver as kernel::auxiliary::Driver>::probe) in archive vmlinux.a
   >>> referenced 54 more times
--
>> ld.lld: error: undefined symbol: __asan_report_load_n
   >>> referenced by mod.rs:3753 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/intrinsics/mod.rs:3753)
   >>>               drivers/android/binder/rust_binder_main.o:(<[u8]>::copy_from_slice) in archive vmlinux.a
   >>> referenced by mod.rs:3753 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/intrinsics/mod.rs:3753)
   >>>               drivers/android/binder/rust_binder_main.o:(<[u8]>::copy_from_slice) in archive vmlinux.a
   >>> referenced by mod.rs:864 (/opt/cross/rustc-1.88.0-bindgen-0.72.1/rustup/toolchains/1.88.0-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:864)
   >>>               drivers/android/binder/rust_binder_main.o:(<rust_binder_main::range_alloc::tree::Descriptor<rust_binder_main::allocation::AllocationInfo>>::try_change_state::<<rust_binder_main::range_alloc::tree::TreeRangeAllocator<rust_binder_main::allocation::AllocationInfo>>::reservation_abort::{closure#1}, (rust_binder_main::range_alloc::Reservation, kernel::rbtree::RBTreeNodeReservation<(usize, usize), ()>)>) in archive vmlinux.a
   >>> referenced 81 more times
..

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Danilo Krummrich 1 week, 1 day ago 
On Wed Mar 25, 2026 at 10:26 AM CET, Alice Ryhl wrote:
> We do not pass -fsanitize-recover to clang, so for consistency we should
> not pass -Zsanitizer-recover to rustc. Thus, remove these flags.

Isn't this because clang forces it regardless? Is this true for rustc as well?
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Alice Ryhl 1 week, 1 day ago 
On Wed, Mar 25, 2026 at 12:06:50PM +0100, Danilo Krummrich wrote:
> On Wed Mar 25, 2026 at 10:26 AM CET, Alice Ryhl wrote:
> > We do not pass -fsanitize-recover to clang, so for consistency we should
> > not pass -Zsanitizer-recover to rustc. Thus, remove these flags.
> 
> Isn't this because clang forces it regardless? Is this true for rustc as well?

I forgot to mention this in commit, but I'm actually a bit confused
about the situation here. If clang forces it somehow, how? I don't think
rustc does anything like that, but not sure. If it doesn't, but clang
does, then maybe rustc should too? Depends on how that happens.

Alice
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Danilo Krummrich 1 week, 1 day ago 
On Wed Mar 25, 2026 at 12:47 PM CET, Alice Ryhl wrote:
> On Wed, Mar 25, 2026 at 12:06:50PM +0100, Danilo Krummrich wrote:
>> On Wed Mar 25, 2026 at 10:26 AM CET, Alice Ryhl wrote:
>> > We do not pass -fsanitize-recover to clang, so for consistency we should
>> > not pass -Zsanitizer-recover to rustc. Thus, remove these flags.
>> 
>> Isn't this because clang forces it regardless? Is this true for rustc as well?
>
> I forgot to mention this in commit, but I'm actually a bit confused
> about the situation here. If clang forces it somehow, how?

I previously had a very brief look at the source code and came across this [1],
where

	static const SanitizerMask AlwaysRecoverable = SanitizerKind::KernelAddress |
	                                               SanitizerKind::KernelHWAddress |
	                                               SanitizerKind::KCFI;

But again, I only had a very brief look and it might well be that I got this
wrong.

[1] https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/SanitizerArgs.cpp#L750

> I don't think rustc does anything like that, but not sure. If it doesn't, but
> clang does, then maybe rustc should too? Depends on how that happens.
>
> Alice
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Gary Guo 1 week, 1 day ago 
On Wed Mar 25, 2026 at 2:04 PM GMT, Danilo Krummrich wrote:
> On Wed Mar 25, 2026 at 12:47 PM CET, Alice Ryhl wrote:
>> On Wed, Mar 25, 2026 at 12:06:50PM +0100, Danilo Krummrich wrote:
>>> On Wed Mar 25, 2026 at 10:26 AM CET, Alice Ryhl wrote:
>>> > We do not pass -fsanitize-recover to clang, so for consistency we should
>>> > not pass -Zsanitizer-recover to rustc. Thus, remove these flags.
>>> 
>>> Isn't this because clang forces it regardless? Is this true for rustc as well?
>>
>> I forgot to mention this in commit, but I'm actually a bit confused
>> about the situation here. If clang forces it somehow, how?
>
> I previously had a very brief look at the source code and came across this [1],
> where
>
> 	static const SanitizerMask AlwaysRecoverable = SanitizerKind::KernelAddress |
> 	                                               SanitizerKind::KernelHWAddress |
> 	                                               SanitizerKind::KCFI;
>
> But again, I only had a very brief look and it might well be that I got this
> wrong.
>
> [1] https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/SanitizerArgs.cpp#L750
>
>> I don't think rustc does anything like that, but not sure. If it doesn't, but
>> clang does, then maybe rustc should too? Depends on how that happens.

It looks like there's no similar logic, and Rustc is passing recoverable
settings based on the command line options:

https://github.com/rust-lang/rust/blob/8a703520e80d87d4423c01f9d4fbc9e5f6533a02/compiler/rustc_codegen_llvm/src/back/write.rs#L644

Best,
Gary
Re: [PATCH 1/2] rust: kasan: do not pass -Zsanitizer-recover
Posted by Alice Ryhl 6 days, 14 hours ago 
On Wed, Mar 25, 2026 at 3:30 PM Gary Guo <gary@garyguo.net> wrote:
>
> On Wed Mar 25, 2026 at 2:04 PM GMT, Danilo Krummrich wrote:
> > On Wed Mar 25, 2026 at 12:47 PM CET, Alice Ryhl wrote:
> >> On Wed, Mar 25, 2026 at 12:06:50PM +0100, Danilo Krummrich wrote:
> >>> On Wed Mar 25, 2026 at 10:26 AM CET, Alice Ryhl wrote:
> >>> > We do not pass -fsanitize-recover to clang, so for consistency we should
> >>> > not pass -Zsanitizer-recover to rustc. Thus, remove these flags.
> >>>
> >>> Isn't this because clang forces it regardless? Is this true for rustc as well?
> >>
> >> I forgot to mention this in commit, but I'm actually a bit confused
> >> about the situation here. If clang forces it somehow, how?
> >
> > I previously had a very brief look at the source code and came across this [1],
> > where
> >
> >       static const SanitizerMask AlwaysRecoverable = SanitizerKind::KernelAddress |
> >                                                      SanitizerKind::KernelHWAddress |
> >                                                      SanitizerKind::KCFI;
> >
> > But again, I only had a very brief look and it might well be that I got this
> > wrong.
> >
> > [1] https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/SanitizerArgs.cpp#L750
> >
> >> I don't think rustc does anything like that, but not sure. If it doesn't, but
> >> clang does, then maybe rustc should too? Depends on how that happens.
>
> It looks like there's no similar logic, and Rustc is passing recoverable
> settings based on the command line options:
>
> https://github.com/rust-lang/rust/blob/8a703520e80d87d4423c01f9d4fbc9e5f6533a02/compiler/rustc_codegen_llvm/src/back/write.rs#L644

Based on
https://lore.kernel.org/all/202603271853.RhfDTdOp-lkp@intel.com/
it seems like you all are right. There is a rustc/clang difference here.

Alice

Patchew 2.1-devel-ea86937

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