在2024年3月28日三月 下午2:27，Jiaxun Yang写道： > thread_info.syscall is used by syscall_get_nr to supply syscall nr > over a thread stack frame. > > Previously, thread_info.syscall is only saved at syscall_trace_enter > when syscall tracing is enabled. However rest of the kernel code do > expect syscall_get_nr to be available without syscall tracing. The > previous design breaks collect_syscall. > > Move saving process to syscall entry to fix it. > > Reported-by: Xi Ruoyao <xry111@xxxxxxxxxxx> > Link: https://github.com/util-linux/util-linux/issues/2867 > Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> Ping, this needs to be in fixes tree. Thanks > --- > arch/mips/include/asm/ptrace.h | 2 +- > arch/mips/kernel/asm-offsets.c | 1 + > arch/mips/kernel/ptrace.c | 15 ++++++--------- > arch/mips/kernel/scall32-o32.S | 23 +++++++++++++---------- > arch/mips/kernel/scall64-n32.S | 3 ++- > arch/mips/kernel/scall64-n64.S | 3 ++- > arch/mips/kernel/scall64-o32.S | 33 +++++++++++++++++---------------- > 7 files changed, 42 insertions(+), 38 deletions(-) > > diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h > index d14d0e37ad02..4a2b40ce39e0 100644 > --- a/arch/mips/include/asm/ptrace.h > +++ b/arch/mips/include/asm/ptrace.h > @@ -159,7 +159,7 @@ extern unsigned long exception_ip(struct pt_regs *regs); > #define exception_ip(regs) exception_ip(regs) > #define profile_pc(regs) instruction_pointer(regs) > > -extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall); > +extern asmlinkage long syscall_trace_enter(struct pt_regs *regs); > extern asmlinkage void syscall_trace_leave(struct pt_regs *regs); > > extern void die(const char *, struct pt_regs *) __noreturn; > diff --git a/arch/mips/kernel/asm-offsets.c > b/arch/mips/kernel/asm-offsets.c > index d1b11f66f748..cb1045ebab06 100644 > --- a/arch/mips/kernel/asm-offsets.c > +++ b/arch/mips/kernel/asm-offsets.c > @@ -101,6 +101,7 @@ void output_thread_info_defines(void) > OFFSET(TI_CPU, thread_info, cpu); > OFFSET(TI_PRE_COUNT, thread_info, preempt_count); > OFFSET(TI_REGS, thread_info, regs); > + OFFSET(TI_SYSCALL, thread_info, syscall); > DEFINE(_THREAD_SIZE, THREAD_SIZE); > DEFINE(_THREAD_MASK, THREAD_MASK); > DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE); > diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c > index 59288c13b581..61503a36067e 100644 > --- a/arch/mips/kernel/ptrace.c > +++ b/arch/mips/kernel/ptrace.c > @@ -1317,16 +1317,13 @@ long arch_ptrace(struct task_struct *child, > long request, > * Notification of system call entry/exit > * - triggered by current->work.syscall_trace > */ > -asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall) > +asmlinkage long syscall_trace_enter(struct pt_regs *regs) > { > user_exit(); > > - current_thread_info()->syscall = syscall; > - > if (test_thread_flag(TIF_SYSCALL_TRACE)) { > if (ptrace_report_syscall_entry(regs)) > return -1; > - syscall = current_thread_info()->syscall; > } > > #ifdef CONFIG_SECCOMP > @@ -1335,7 +1332,7 @@ asmlinkage long syscall_trace_enter(struct > pt_regs *regs, long syscall) > struct seccomp_data sd; > unsigned long args[6]; > > - sd.nr = syscall; > + sd.nr = current_thread_info()->syscall; > sd.arch = syscall_get_arch(current); > syscall_get_arguments(current, regs, args); > for (i = 0; i < 6; i++) > @@ -1345,23 +1342,23 @@ asmlinkage long syscall_trace_enter(struct > pt_regs *regs, long syscall) > ret = __secure_computing(&sd); > if (ret == -1) > return ret; > - syscall = current_thread_info()->syscall; > } > #endif > > if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) > trace_sys_enter(regs, regs->regs[2]); > > - audit_syscall_entry(syscall, regs->regs[4], regs->regs[5], > + audit_syscall_entry(current_thread_info()->syscall, > + regs->regs[4], regs->regs[5], > regs->regs[6], regs->regs[7]); > > /* > * Negative syscall numbers are mistaken for rejected syscalls, but > * won't have had the return value set appropriately, so we do so now. > */ > - if (syscall < 0) > + if (current_thread_info()->syscall < 0) > syscall_set_return_value(current, regs, -ENOSYS, 0); > - return syscall; > + return current_thread_info()->syscall; > } > > /* > diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S > index 18dc9b345056..2c604717e630 100644 > --- a/arch/mips/kernel/scall32-o32.S > +++ b/arch/mips/kernel/scall32-o32.S > @@ -77,6 +77,18 @@ loads_done: > PTR_WD load_a7, bad_stack_a7 > .previous > > + /* > + * syscall number is in v0 unless we called syscall(__NR_###) > + * where the real syscall number is in a0 > + */ > + subu t2, v0, __NR_O32_Linux > + bnez t2, 1f /* __NR_syscall at offset 0 */ > + LONG_S a0, TI_SYSCALL($28) # Save a0 as syscall number > + b 2f > +1: > + LONG_S v0, TI_SYSCALL($28) # Save v0 as syscall number > +2: > + > lw t0, TI_FLAGS($28) # syscall tracing enabled? > li t1, _TIF_WORK_SYSCALL_ENTRY > and t0, t1 > @@ -114,16 +126,7 @@ syscall_trace_entry: > SAVE_STATIC > move a0, sp > > - /* > - * syscall number is in v0 unless we called syscall(__NR_###) > - * where the real syscall number is in a0 > - */ > - move a1, v0 > - subu t2, v0, __NR_O32_Linux > - bnez t2, 1f /* __NR_syscall at offset 0 */ > - lw a1, PT_R4(sp) > - > -1: jal syscall_trace_enter > + jal syscall_trace_enter > > bltz v0, 1f # seccomp failed? Skip syscall > > diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S > index 97456b2ca7dc..97788859238c 100644 > --- a/arch/mips/kernel/scall64-n32.S > +++ b/arch/mips/kernel/scall64-n32.S > @@ -44,6 +44,8 @@ NESTED(handle_sysn32, PT_SIZE, sp) > > sd a3, PT_R26(sp) # save a3 for syscall restarting > > + LONG_S v0, TI_SYSCALL($28) # Store syscall number > + > li t1, _TIF_WORK_SYSCALL_ENTRY > LONG_L t0, TI_FLAGS($28) # syscall tracing enabled? > and t0, t1, t0 > @@ -72,7 +74,6 @@ syscall_common: > n32_syscall_trace_entry: > SAVE_STATIC > move a0, sp > - move a1, v0 > jal syscall_trace_enter > > bltz v0, 1f # seccomp failed? Skip syscall > diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S > index e6264aa62e45..be11ea5cc67e 100644 > --- a/arch/mips/kernel/scall64-n64.S > +++ b/arch/mips/kernel/scall64-n64.S > @@ -46,6 +46,8 @@ NESTED(handle_sys64, PT_SIZE, sp) > > sd a3, PT_R26(sp) # save a3 for syscall restarting > > + LONG_S v0, TI_SYSCALL($28) # Store syscall number > + > li t1, _TIF_WORK_SYSCALL_ENTRY > LONG_L t0, TI_FLAGS($28) # syscall tracing enabled? > and t0, t1, t0 > @@ -82,7 +84,6 @@ n64_syscall_exit: > syscall_trace_entry: > SAVE_STATIC > move a0, sp > - move a1, v0 > jal syscall_trace_enter > > bltz v0, 1f # seccomp failed? Skip syscall > diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S > index d3c2616cba22..7a5abb73e531 100644 > --- a/arch/mips/kernel/scall64-o32.S > +++ b/arch/mips/kernel/scall64-o32.S > @@ -79,6 +79,22 @@ loads_done: > PTR_WD load_a7, bad_stack_a7 > .previous > > + /* > + * absolute syscall number is in v0 unless we called syscall(__NR_###) > + * where the real syscall number is in a0 > + * note: NR_syscall is the first O32 syscall but the macro is > + * only defined when compiling with -mabi=32 (CONFIG_32BIT) > + * therefore __NR_O32_Linux is used (4000) > + */ > + > + subu t2, v0, __NR_O32_Linux > + bnez t2, 1f /* __NR_syscall at offset 0 */ > + LONG_S a0, TI_SYSCALL($28) # Save a0 as syscall number > + b 2f > +1: > + LONG_S v0, TI_SYSCALL($28) # Save v0 as syscall number > +2: > + > li t1, _TIF_WORK_SYSCALL_ENTRY > LONG_L t0, TI_FLAGS($28) # syscall tracing enabled? > and t0, t1, t0 > @@ -113,22 +129,7 @@ trace_a_syscall: > sd a7, PT_R11(sp) # For indirect syscalls > > move a0, sp > - /* > - * absolute syscall number is in v0 unless we called syscall(__NR_###) > - * where the real syscall number is in a0 > - * note: NR_syscall is the first O32 syscall but the macro is > - * only defined when compiling with -mabi=32 (CONFIG_32BIT) > - * therefore __NR_O32_Linux is used (4000) > - */ > - .set push > - .set reorder > - subu t1, v0, __NR_O32_Linux > - move a1, v0 > - bnez t1, 1f /* __NR_syscall at offset 0 */ > - ld a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ > - .set pop > - > -1: jal syscall_trace_enter > + jal syscall_trace_enter > > bltz v0, 1f # seccomp failed? Skip syscall > > > --- > base-commit: a6bd6c9333397f5a0e2667d4d82fef8c970108f2 > change-id: 20240328-mips_save_syscall-be471311cc9b > > Best regards, > -- > Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> -- - Jiaxun
