arch/loongarch/kernel/vdso.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
The current size of VDSO code mapping is hardcoded to PAGE_SIZE. This
cannot work for 4KB page size after commit 18efd0b10e0fd77 ("LoongArch:
vDSO: Wire up getrandom() vDSO implementation") because the code size
increases to 8KB. Thus set the code mapping size to its real size, i.e.
PAGE_ALIGN(vdso_end - vdso_start).
Fixes: 18efd0b10e0fd77 ("LoongArch: vDSO: Wire up getrandom() vDSO implementation")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
arch/loongarch/kernel/vdso.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index f6fcc52aefae..7e0cc7f5e1ed 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -85,7 +85,6 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
struct loongarch_vdso_info vdso_info = {
.vdso = vdso_start,
- .size = PAGE_SIZE,
.code_mapping = {
.name = "[vdso]",
.pages = vdso_pages,
@@ -103,7 +102,7 @@ static int __init init_vdso(void)
unsigned long i, cpu, pfn;
BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
- BUG_ON(!PAGE_ALIGNED(vdso_info.size));
+ vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start);
for_each_possible_cpu(cpu)
vdso_pdata[cpu].node = cpu_to_node(cpu);
--
2.43.5
On Sun, 2024-09-29 at 15:49 +0800, Huacai Chen wrote: > The current size of VDSO code mapping is hardcoded to PAGE_SIZE. This > cannot work for 4KB page size after commit 18efd0b10e0fd77 ("LoongArch: > vDSO: Wire up getrandom() vDSO implementation") because the code size > increases to 8KB. Thus set the code mapping size to its real size, i.e. > PAGE_ALIGN(vdso_end - vdso_start). I get: $ size vdso.so text data bss dec hex filename 3716 328 0 4044 fcc vdso.so So it "just" fits in 4 KiB, and of course it may exceed 4 KiB with a different compiler or some kernel configuration affecting code generation like CONFIG_INIT_STACK_ALL_ZERO or CONFIG_ZERO_CALL_USED_REGS). I remember I've checked `size vdso.so` before but I cannot remember why I didn't realize a problem here. Sorry for the stupidity. Reviewed-by: Xi Ruoyao <xry111@xry111.site> > > Fixes: 18efd0b10e0fd77 ("LoongArch: vDSO: Wire up getrandom() vDSO implementation") > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> > --- > arch/loongarch/kernel/vdso.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c > index f6fcc52aefae..7e0cc7f5e1ed 100644 > --- a/arch/loongarch/kernel/vdso.c > +++ b/arch/loongarch/kernel/vdso.c > @@ -85,7 +85,6 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, > > struct loongarch_vdso_info vdso_info = { > .vdso = vdso_start, > - .size = PAGE_SIZE, > .code_mapping = { > .name = "[vdso]", > .pages = vdso_pages, > @@ -103,7 +102,7 @@ static int __init init_vdso(void) > unsigned long i, cpu, pfn; > > BUG_ON(!PAGE_ALIGNED(vdso_info.vdso)); > - BUG_ON(!PAGE_ALIGNED(vdso_info.size)); > + vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start); > > for_each_possible_cpu(cpu) > vdso_pdata[cpu].node = cpu_to_node(cpu); -- Xi Ruoyao <xry111@xry111.site> School of Aerospace Science and Technology, Xidian University
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