From: Helge Deller deller@gmx.de
stable inclusion from stable-5.10.80 commit fc42bbb7827be96c4a77c5ff490b84316c5f963b bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 279917e27edc293eb645a25428c6ab3f3bca3f86 upstream.
I noticed that sometimes at kernel startup the backtraces did not included the function names of init functions. Their address were not resolved to function names and instead only the address was printed.
Debugging shows that the culprit is is_ksym_addr() which is called by the backtrace functions to check if an address belongs to a function in the kernel. The problem occurs only for CONFIG_KALLSYMS_ALL=y.
When looking at is_ksym_addr() one can see that for CONFIG_KALLSYMS_ALL=y the function only tries to resolve the address via is_kernel() function, which checks like this: if (addr >= _stext && addr <= _end) return 1; On parisc the init functions are located before _stext, so this check fails. Other platforms seem to have all functions (including init functions) behind _stext.
The following patch moves the _stext symbol at the beginning of the kernel and thus includes the init section. This fixes the check and does not seem to have any negative side effects on where the kernel mapping happens in the map_pages() function in arch/parisc/mm/init.c.
Signed-off-by: Helge Deller deller@gmx.de Cc: stable@kernel.org # 5.4+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Weilong Chen chenweilong@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/parisc/kernel/vmlinux.lds.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S index 2769eb991f58..3d208afd15bc 100644 --- a/arch/parisc/kernel/vmlinux.lds.S +++ b/arch/parisc/kernel/vmlinux.lds.S @@ -57,6 +57,8 @@ SECTIONS { . = KERNEL_BINARY_TEXT_START;
+ _stext = .; /* start of kernel text, includes init code & data */ + __init_begin = .; HEAD_TEXT_SECTION MLONGCALL_DISCARD(INIT_TEXT_SECTION(8)) @@ -80,7 +82,6 @@ SECTIONS /* freed after init ends here */
_text = .; /* Text and read-only data */ - _stext = .; MLONGCALL_KEEP(INIT_TEXT_SECTION(8)) .text ALIGN(PAGE_SIZE) : { TEXT_TEXT