From: Alexandre Ghiti <alexghiti@rivosinc.com> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, Zong Li <zong.li@sifive.com>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alexandre Ghiti <alexghiti@rivosinc.com>, syzbot+2c2a76232878c44e0eae@syzkaller.appspotmail.com Subject: [PATCH -fixes] riscv: Check if the code to patch lies in the exit section Date: Wed, 6 Dec 2023 17:54:58 +0100 [thread overview] Message-ID: <20231206165458.40610-1-alexghiti@rivosinc.com> (raw) Otherwise we fall through to vmalloc_to_page() which panics since the address does not lie in the vmalloc region. Fixes: 043cb41a85de ("riscv: introduce interfaces to patch kernel code") Reported-by: syzbot+2c2a76232878c44e0eae@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000ce4a27060b39ed34@google.com/T/ Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- arch/riscv/include/asm/sections.h | 1 + arch/riscv/kernel/patch.c | 11 ++++++++++- arch/riscv/kernel/vmlinux.lds.S | 2 ++ 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h index 32336e8a17cb..a393d5035c54 100644 --- a/arch/riscv/include/asm/sections.h +++ b/arch/riscv/include/asm/sections.h @@ -13,6 +13,7 @@ extern char _start_kernel[]; extern char __init_data_begin[], __init_data_end[]; extern char __init_text_begin[], __init_text_end[]; extern char __alt_start[], __alt_end[]; +extern char __exittext_begin[], __exittext_end[]; static inline bool is_va_kernel_text(uintptr_t va) { diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 13ee7bf589a1..37e87fdcf6a0 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -14,6 +14,7 @@ #include <asm/fixmap.h> #include <asm/ftrace.h> #include <asm/patch.h> +#include <asm/sections.h> struct patch_insn { void *addr; @@ -25,6 +26,14 @@ struct patch_insn { int riscv_patch_in_stop_machine = false; #ifdef CONFIG_MMU + +static inline bool is_kernel_exittext(uintptr_t addr) +{ + return system_state < SYSTEM_RUNNING && + addr >= (uintptr_t)__exittext_begin && + addr < (uintptr_t)__exittext_end; +} + /* * The fix_to_virt(, idx) needs a const value (not a dynamic variable of * reg-a0) or BUILD_BUG_ON failed with "idx >= __end_of_fixed_addresses". @@ -35,7 +44,7 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) uintptr_t uintaddr = (uintptr_t) addr; struct page *page; - if (core_kernel_text(uintaddr)) + if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) page = phys_to_page(__pa_symbol(addr)); else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) page = vmalloc_to_page(addr); diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 492dd4b8f3d6..002ca58dd998 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -69,10 +69,12 @@ SECTIONS __soc_builtin_dtb_table_end = .; } /* we have to discard exit text and such at runtime, not link time */ + __exittext_begin = .; .exit.text : { EXIT_TEXT } + __exittext_end = .; __init_text_end = .; . = ALIGN(SECTION_ALIGN); -- 2.39.2
WARNING: multiple messages have this Message-ID (diff)
From: Alexandre Ghiti <alexghiti@rivosinc.com> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, Zong Li <zong.li@sifive.com>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alexandre Ghiti <alexghiti@rivosinc.com>, syzbot+2c2a76232878c44e0eae@syzkaller.appspotmail.com Subject: [PATCH -fixes] riscv: Check if the code to patch lies in the exit section Date: Wed, 6 Dec 2023 17:54:58 +0100 [thread overview] Message-ID: <20231206165458.40610-1-alexghiti@rivosinc.com> (raw) Otherwise we fall through to vmalloc_to_page() which panics since the address does not lie in the vmalloc region. Fixes: 043cb41a85de ("riscv: introduce interfaces to patch kernel code") Reported-by: syzbot+2c2a76232878c44e0eae@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000ce4a27060b39ed34@google.com/T/ Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- arch/riscv/include/asm/sections.h | 1 + arch/riscv/kernel/patch.c | 11 ++++++++++- arch/riscv/kernel/vmlinux.lds.S | 2 ++ 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h index 32336e8a17cb..a393d5035c54 100644 --- a/arch/riscv/include/asm/sections.h +++ b/arch/riscv/include/asm/sections.h @@ -13,6 +13,7 @@ extern char _start_kernel[]; extern char __init_data_begin[], __init_data_end[]; extern char __init_text_begin[], __init_text_end[]; extern char __alt_start[], __alt_end[]; +extern char __exittext_begin[], __exittext_end[]; static inline bool is_va_kernel_text(uintptr_t va) { diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 13ee7bf589a1..37e87fdcf6a0 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -14,6 +14,7 @@ #include <asm/fixmap.h> #include <asm/ftrace.h> #include <asm/patch.h> +#include <asm/sections.h> struct patch_insn { void *addr; @@ -25,6 +26,14 @@ struct patch_insn { int riscv_patch_in_stop_machine = false; #ifdef CONFIG_MMU + +static inline bool is_kernel_exittext(uintptr_t addr) +{ + return system_state < SYSTEM_RUNNING && + addr >= (uintptr_t)__exittext_begin && + addr < (uintptr_t)__exittext_end; +} + /* * The fix_to_virt(, idx) needs a const value (not a dynamic variable of * reg-a0) or BUILD_BUG_ON failed with "idx >= __end_of_fixed_addresses". @@ -35,7 +44,7 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) uintptr_t uintaddr = (uintptr_t) addr; struct page *page; - if (core_kernel_text(uintaddr)) + if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) page = phys_to_page(__pa_symbol(addr)); else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) page = vmalloc_to_page(addr); diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 492dd4b8f3d6..002ca58dd998 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -69,10 +69,12 @@ SECTIONS __soc_builtin_dtb_table_end = .; } /* we have to discard exit text and such at runtime, not link time */ + __exittext_begin = .; .exit.text : { EXIT_TEXT } + __exittext_end = .; __init_text_end = .; . = ALIGN(SECTION_ALIGN); -- 2.39.2 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2023-12-06 16:55 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-12-06 16:54 Alexandre Ghiti [this message] 2023-12-06 16:54 ` [PATCH -fixes] riscv: Check if the code to patch lies in the exit section Alexandre Ghiti 2023-12-08 16:10 ` patchwork-bot+linux-riscv 2023-12-08 16:10 ` patchwork-bot+linux-riscv
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