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[PW_SID:973936] Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"#553

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[PW_SID:973936] Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"#553
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@linux-riscv-bot linux-riscv-bot commented Jun 19, 2025

PR for series 973936 applied to workflow__riscv__fixes

Name: Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=973936
Version: 1

Linux RISC-V bot and others added 2 commits June 12, 2025 20:20
Adding CI files
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Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"
329a562 
This reverts commit ad5643c ("riscv: Define TASK_SIZE_MAX for
__access_ok()").

This commit changes TASK_SIZE_MAX to be LONG_MAX to optimize access_ok(),
because the previous TASK_SIZE_MAX (default to TASK_SIZE) requires some
computation.

The reasoning was that all user addresses are less than LONG_MAX, and all
kernel addresses are greater than LONG_MAX. Therefore access_ok() can
filter kernel addresses.

Addresses between TASK_SIZE and LONG_MAX are not valid user addresses, but
access_ok() let them pass. That was thought to be okay, because they are
not valid addresses at hardware level.

Unfortunately, one case is missed: get_user_pages_fast() happily accepts
addresses between TASK_SIZE and LONG_MAX. futex(), for instance, uses
get_user_pages_fast(). This causes the problem reported by Robert [1].

Therefore, revert this commit. TASK_SIZE_MAX is changed to the default:
TASK_SIZE.

This unfortunately reduces performance, because TASK_SIZE is more expensive
to compute compared to LONG_MAX. But correctness first, we can think about
optimization later, if required.

Reported-by: <rtm@csail.mit.edu>
Closes: https://lore.kernel.org/linux-riscv/77605.1750245028@localhost/
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 104.17 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 2001.13 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 2699.49 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 20.96 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 22.04 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 0.68 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 71.83 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.23 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
kdoc
Desc: Detects for kdoc errors
Duration: 0.78 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
module-param
Desc: Detect module_param changes
Duration: 0.25 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.22 seconds
Result: PASS

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linux-riscv-bot commented Jun 19, 2025

Patch 1: "Revert "riscv: Define TASK_SIZE_MAX for __access_ok()""
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.30 seconds
Result: PASS

@linux-riscv-bot linux-riscv-bot force-pushed the workflow__riscv__fixes branch 2 times, most recently from 6ce2eef to b5ded79 Compare June 24, 2025 01:05
@linux-riscv-bot linux-riscv-bot deleted the pw973936 branch June 24, 2025 01:06
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