This is a note to let you know that I've just added the patch titled powerpc/ptrace: Don't return error when getting/setting FP regs without CONFIG_PPC_FPU_REGS to the 5.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-ptrace-don-t-return-error-when-getting-setting-fp-regs-without-config_ppc_fpu_regs.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 3618250c8399cb36f4a0fbc48610a178307e1c64 Mon Sep 17 00:00:00 2001 From: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Date: Wed, 31 Mar 2021 14:14:58 +0000 Subject: powerpc/ptrace: Don't return error when getting/setting FP regs without CONFIG_PPC_FPU_REGS From: Christophe Leroy <christophe.leroy@xxxxxxxxxx> commit 3618250c8399cb36f4a0fbc48610a178307e1c64 upstream. An #ifdef CONFIG_PPC_FPU_REGS is missing in arch_ptrace() leading to the following Oops because [REGSET_FPR] entry is not initialised in native_regsets[]. [ 41.917608] BUG: Unable to handle kernel instruction fetch [ 41.922849] Faulting instruction address: 0xff8fd228 [ 41.927760] Oops: Kernel access of bad area, sig: 11 [#1] [ 41.933089] BE PAGE_SIZE=4K PREEMPT CMPC885 [ 41.940753] Modules linked in: [ 41.943768] CPU: 0 PID: 366 Comm: gdb Not tainted 5.12.0-rc5-s3k-dev-01666-g7aac86a0f057-dirty #4835 [ 41.952800] NIP: ff8fd228 LR: c004d9e0 CTR: ff8fd228 [ 41.957790] REGS: caae9df0 TRAP: 0400 Not tainted (5.12.0-rc5-s3k-dev-01666-g7aac86a0f057-dirty) [ 41.966741] MSR: 40009032 <EE,ME,IR,DR,RI> CR: 82004248 XER: 20000000 [ 41.973540] [ 41.973540] GPR00: c004d9b4 caae9eb0 c1b64f60 c1b64520 c0713cd4 caae9eb8 c1bacdfc 00000004 [ 41.973540] GPR08: 00000200 ff8fd228 c1bac700 00001032 28004242 1061aaf4 00000001 106d64a0 [ 41.973540] GPR16: 00000000 00000000 7fa0a774 10610000 7fa0aef9 00000000 10610000 7fa0a538 [ 41.973540] GPR24: 7fa0a580 7fa0a570 c1bacc00 c1b64520 c1bacc00 caae9ee8 00000108 c0713cd4 [ 42.009685] NIP [ff8fd228] 0xff8fd228 [ 42.013300] LR [c004d9e0] __regset_get+0x100/0x124 [ 42.018036] Call Trace: [ 42.020443] [caae9eb0] [c004d9b4] __regset_get+0xd4/0x124 (unreliable) [ 42.026899] [caae9ee0] [c004da94] copy_regset_to_user+0x5c/0xb0 [ 42.032751] [caae9f10] [c002f640] sys_ptrace+0xe4/0x588 [ 42.037915] [caae9f30] [c0011010] ret_from_syscall+0x0/0x28 [ 42.043422] --- interrupt: c00 at 0xfd1f8e4 [ 42.047553] NIP: 0fd1f8e4 LR: 1004a688 CTR: 00000000 [ 42.052544] REGS: caae9f40 TRAP: 0c00 Not tainted (5.12.0-rc5-s3k-dev-01666-g7aac86a0f057-dirty) [ 42.061494] MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 48004442 XER: 00000000 [ 42.068551] [ 42.068551] GPR00: 0000001a 7fa0a040 77dad7e0 0000000e 00000170 00000000 7fa0a078 00000004 [ 42.068551] GPR08: 00000000 108deb88 108dda40 106d6010 44004442 1061aaf4 00000001 106d64a0 [ 42.068551] GPR16: 00000000 00000000 7fa0a774 10610000 7fa0aef9 00000000 10610000 7fa0a538 [ 42.068551] GPR24: 7fa0a580 7fa0a570 1078fe00 1078fd70 1078fd70 00000170 0fdd3244 0000000d [ 42.104696] NIP [0fd1f8e4] 0xfd1f8e4 [ 42.108225] LR [1004a688] 0x1004a688 [ 42.111753] --- interrupt: c00 [ 42.114768] Instruction dump: [ 42.117698] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 42.125443] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 42.133195] ---[ end trace d35616f22ab2100c ]--- Adding the missing #ifdef is not good because gdb doesn't like getting an error when getting registers. Instead, make ptrace return 0s when CONFIG_PPC_FPU_REGS is not set. Fixes: b6254ced4da6 ("powerpc/signal: Don't manage floating point regs when no FPU") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/9121a44a2d50ba1af18d8aa5ada06c9a3bea8afd.1617200085.git.christophe.leroy@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/ptrace/Makefile | 4 ++-- arch/powerpc/kernel/ptrace/ptrace-decl.h | 14 -------------- arch/powerpc/kernel/ptrace/ptrace-fpu.c | 10 ++++++++++ arch/powerpc/kernel/ptrace/ptrace-novsx.c | 8 ++++++++ arch/powerpc/kernel/ptrace/ptrace-view.c | 2 -- 5 files changed, 20 insertions(+), 18 deletions(-) --- a/arch/powerpc/kernel/ptrace/Makefile +++ b/arch/powerpc/kernel/ptrace/Makefile @@ -6,11 +6,11 @@ CFLAGS_ptrace-view.o += -DUTS_MACHINE='"$(UTS_MACHINE)"' obj-y += ptrace.o ptrace-view.o -obj-$(CONFIG_PPC_FPU_REGS) += ptrace-fpu.o +obj-y += ptrace-fpu.o obj-$(CONFIG_COMPAT) += ptrace32.o obj-$(CONFIG_VSX) += ptrace-vsx.o ifneq ($(CONFIG_VSX),y) -obj-$(CONFIG_PPC_FPU_REGS) += ptrace-novsx.o +obj-y += ptrace-novsx.o endif obj-$(CONFIG_ALTIVEC) += ptrace-altivec.o obj-$(CONFIG_SPE) += ptrace-spe.o --- a/arch/powerpc/kernel/ptrace/ptrace-decl.h +++ b/arch/powerpc/kernel/ptrace/ptrace-decl.h @@ -165,22 +165,8 @@ int ptrace_put_reg(struct task_struct *t extern const struct user_regset_view user_ppc_native_view; /* ptrace-fpu */ -#ifdef CONFIG_PPC_FPU_REGS int ptrace_get_fpr(struct task_struct *child, int index, unsigned long *data); int ptrace_put_fpr(struct task_struct *child, int index, unsigned long data); -#else -static inline int -ptrace_get_fpr(struct task_struct *child, int index, unsigned long *data) -{ - return -EIO; -} - -static inline int -ptrace_put_fpr(struct task_struct *child, int index, unsigned long data) -{ - return -EIO; -} -#endif /* ptrace-(no)adv */ void ppc_gethwdinfo(struct ppc_debug_info *dbginfo); --- a/arch/powerpc/kernel/ptrace/ptrace-fpu.c +++ b/arch/powerpc/kernel/ptrace/ptrace-fpu.c @@ -8,32 +8,42 @@ int ptrace_get_fpr(struct task_struct *child, int index, unsigned long *data) { +#ifdef CONFIG_PPC_FPU_REGS unsigned int fpidx = index - PT_FPR0; +#endif if (index > PT_FPSCR) return -EIO; +#ifdef CONFIG_PPC_FPU_REGS flush_fp_to_thread(child); if (fpidx < (PT_FPSCR - PT_FPR0)) memcpy(data, &child->thread.TS_FPR(fpidx), sizeof(long)); else *data = child->thread.fp_state.fpscr; +#else + *data = 0; +#endif return 0; } int ptrace_put_fpr(struct task_struct *child, int index, unsigned long data) { +#ifdef CONFIG_PPC_FPU_REGS unsigned int fpidx = index - PT_FPR0; +#endif if (index > PT_FPSCR) return -EIO; +#ifdef CONFIG_PPC_FPU_REGS flush_fp_to_thread(child); if (fpidx < (PT_FPSCR - PT_FPR0)) memcpy(&child->thread.TS_FPR(fpidx), &data, sizeof(long)); else child->thread.fp_state.fpscr = data; +#endif return 0; } --- a/arch/powerpc/kernel/ptrace/ptrace-novsx.c +++ b/arch/powerpc/kernel/ptrace/ptrace-novsx.c @@ -21,12 +21,16 @@ int fpr_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { +#ifdef CONFIG_PPC_FPU_REGS BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) != offsetof(struct thread_fp_state, fpr[32])); flush_fp_to_thread(target); return membuf_write(&to, &target->thread.fp_state, 33 * sizeof(u64)); +#else + return membuf_write(&to, &empty_zero_page, 33 * sizeof(u64)); +#endif } /* @@ -46,6 +50,7 @@ int fpr_set(struct task_struct *target, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { +#ifdef CONFIG_PPC_FPU_REGS BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) != offsetof(struct thread_fp_state, fpr[32])); @@ -53,4 +58,7 @@ int fpr_set(struct task_struct *target, return user_regset_copyin(&pos, &count, &kbuf, &ubuf, &target->thread.fp_state, 0, -1); +#else + return 0; +#endif } --- a/arch/powerpc/kernel/ptrace/ptrace-view.c +++ b/arch/powerpc/kernel/ptrace/ptrace-view.c @@ -522,13 +522,11 @@ static const struct user_regset native_r .size = sizeof(long), .align = sizeof(long), .regset_get = gpr_get, .set = gpr_set }, -#ifdef CONFIG_PPC_FPU_REGS [REGSET_FPR] = { .core_note_type = NT_PRFPREG, .n = ELF_NFPREG, .size = sizeof(double), .align = sizeof(double), .regset_get = fpr_get, .set = fpr_set }, -#endif #ifdef CONFIG_ALTIVEC [REGSET_VMX] = { .core_note_type = NT_PPC_VMX, .n = 34, Patches currently in stable-queue which might be from christophe.leroy@xxxxxxxxxx are queue-5.11/powerpc-ptrace-don-t-return-error-when-getting-setting-fp-regs-without-config_ppc_fpu_regs.patch queue-5.11/powerpc-vdso-make-sure-vdso_wrapper.o-is-rebuilt-everytime-vdso.so-is-rebuilt.patch