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[PW_SID:1123455] riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()#2243

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[PW_SID:1123455] riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()#2243
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@linux-riscv-bot linux-riscv-bot commented Jul 8, 2026

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PR for series 1123455 applied to workflow__riscv__fixes

Name: riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1123455
Version: 1

liutgnu and others added 3 commits July 6, 2026 18:24
@liutgnu
riscv: Prevent NULL pointer dereference in machine_kexec_prepare()
60d607d 
A NULL pointer dereference issue is noticed in riscv's machine_kexec_prepare(),
where image->segment[i].buf might be NULL and copied unchecked.

The NULL buf comes from ima_add_kexec_buffer(), where kbuf is added by
kexec_add_buffer(), but kbuf.buffer is NULL, then it is copied without
a check in machine_kexec_prepare():

  kexec_file_load
    -> kimage_file_alloc_init()
       -> kimage_file_prepare_segments()
          -> ima_add_kexec_buffer()
             -> kexec_add_buffer()
    -> machine_kexec_prepare()
       -> memcpy()

Address this by adding a check before the data copy attempt.

Fixes: b7fb4d7 ("RISC-V: use memcpy for kexec_file mode")
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/kexec/CAO7dBbVftLUhd2qrh7hmijTB3PEPfZAhykCGqEfrPoOcSrrj-w@mail.gmail.com/
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
Link: https://patch.msgid.link/20260705232706.30265-2-ltao@redhat.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Adding CI files
dc5ff20
riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()
06d7d8a 
When dump_backtrace() is called with a NULL task argument, and the
call stack contains functions that are being traced,
walk_stackframe() eventually calls ftrace_graph_ret_addr() with the
NULL task pointer, which results in a NULL pointer dereference when
accessing task->curr_ret_stack.

Fix this by assigning the task pointer to the current task in
walk_stackframe() when it is NULL, keeping the behavior consistent
with other architectures.

Fixes: ecbf894 ("riscv: Fix ftrace_graph_ret_addr() to use the correct task pointer")
Reviewed-by: Shengming Hu <hu.shengming@zte.com.cn>
Reviewed-by: Rui Gao <gao.rui@zte.com.cn>
Reviewed-by: Luo Haiyang <luo.haiyang@zte.com.cn>
Reviewed-by: Run Zhang <zhang.run@zte.com.cn>
Signed-off-by: Anmeng Zhang <zhang.anmeng@zte.com.cn>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 143.02 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1420.28 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1723.70 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 26.08 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 27.77 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 1.84 seconds
Result: WARNING
Output:

CHECK: Comparison to NULL could be written "!task"
#36: FILE: arch/riscv/kernel/stacktrace.c:55:
+	if (task == NULL)

total: 0 errors, 0 warnings, 1 checks, 15 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 06d7d8ab74d7 ("riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 0 warnings, 1 checks, 15 lines checked
CHECK: Comparison to NULL could be written "!task"

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 88.11 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.24 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
kdoc
Desc: Detects for kdoc errors
Duration: 0.86 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
module-param
Desc: Detect module_param changes
Duration: 0.25 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.28 seconds
Result: PASS

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linux-riscv-bot commented Jul 8, 2026

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Patch 1: "riscv: stacktrace: Fix NULL task pointer in ftrace_graph_ret_addr()"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.31 seconds
Result: PASS

@linux-riscv-bot
linux-riscv-bot force-pushed the workflow__riscv__fixes branch 7 times, most recently from f54dc6c to f61148d Compare July 15, 2026 03:51
@linux-riscv-bot
linux-riscv-bot force-pushed the workflow__riscv__fixes branch 2 times, most recently from 56b6f30 to 8ca72ef Compare July 15, 2026 17:25
@linux-riscv-bot
linux-riscv-bot deleted the pw1123455 branch July 16, 2026 01:03
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