| Message ID | 20180309084151.2379-3-alexander.sverdlin@nokia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Alexander, On 9 March 2018 at 08:41, Alexander Sverdlin <alexander.sverdlin@nokia.com> wrote: > Teach ftrace_make_call() and ftrace_make_nop() about PLTs. > Teach PLT code about FTRACE and all its callbacks. > Otherwise the following might happen: > > ------------[ cut here ]------------ > WARNING: CPU: 14 PID: 2265 at .../arch/arm/kernel/insn.c:14 __arm_gen_branch+0x83/0x8c() > ... > Hardware name: LSI Axxia AXM55XX > [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) > [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) > [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) > [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) > [<c03218f3>] (warn_slowpath_null) from [<c03143cf>] (__arm_gen_branch+0x83/0x8c) > [<c03143cf>] (__arm_gen_branch) from [<c0314337>] (ftrace_make_nop+0xf/0x24) > [<c0314337>] (ftrace_make_nop) from [<c038ebcb>] (ftrace_process_locs+0x27b/0x3e8) > [<c038ebcb>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) > [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) > [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) > ---[ end trace e1b64ced7a89adcc ]--- > ------------[ cut here ]------------ > WARNING: CPU: 14 PID: 2265 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1b1/0x234() > ... > Hardware name: LSI Axxia AXM55XX > [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) > [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) > [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) > [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) > [<c03218f3>] (warn_slowpath_null) from [<c038e87d>] (ftrace_bug+0x1b1/0x234) > [<c038e87d>] (ftrace_bug) from [<c038ebd5>] (ftrace_process_locs+0x285/0x3e8) > [<c038ebd5>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) > [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) > [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) > ---[ end trace e1b64ced7a89adcd ]--- > ftrace failed to modify [<e9ef7006>] 0xe9ef7006 > actual: 02:f0:3b:fa > ftrace record flags: 0 > (0) expected tramp: c0314265 > > Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> > --- > arch/arm/include/asm/ftrace.h | 3 +++ > arch/arm/include/asm/module.h | 1 + > arch/arm/kernel/ftrace.c | 62 ++++++++++++++++++++++++++++++++++++------- > arch/arm/kernel/module-plts.c | 53 +++++++++++++++++++++++++++--------- > 4 files changed, 97 insertions(+), 22 deletions(-) > > diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h > index 9e842ff..faeb6b1 100644 > --- a/arch/arm/include/asm/ftrace.h > +++ b/arch/arm/include/asm/ftrace.h > @@ -19,6 +19,9 @@ struct dyn_arch_ftrace { > #ifdef CONFIG_OLD_MCOUNT > bool old_mcount; > #endif > +#ifdef CONFIG_ARM_MODULE_PLTS > + struct module *mod; > +#endif > }; > > static inline unsigned long ftrace_call_adjust(unsigned long addr) > diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h > index 6996405..e3d7a51 100644 > --- a/arch/arm/include/asm/module.h > +++ b/arch/arm/include/asm/module.h > @@ -30,6 +30,7 @@ struct plt_entries { > > struct mod_plt_sec { > struct elf32_shdr *plt; > + struct plt_entries *plt_ent; > int plt_count; > }; > > diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c > index 5617932..b55355f 100644 > --- a/arch/arm/kernel/ftrace.c > +++ b/arch/arm/kernel/ftrace.c > @@ -98,6 +98,19 @@ int ftrace_arch_code_modify_post_process(void) > > static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) > { > + s32 offset = addr - pc; > + s32 blim = 0xfe000008; > + s32 flim = 0x02000004; > + > + if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) { > + blim = 0xff000004; > + flim = 0x01000002; > + } > + > + if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && > + (offset < blim || offset > flim)) > + return 0; > + > return arm_gen_branch_link(pc, addr); > } > > @@ -166,10 +179,22 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) > { > unsigned long new, old; > unsigned long ip = rec->ip; > + unsigned long aaddr = adjust_address(rec, addr); > > old = ftrace_nop_replace(rec); > > - new = ftrace_call_replace(ip, adjust_address(rec, addr)); > + new = ftrace_call_replace(ip, aaddr); > + > +#ifdef CONFIG_ARM_MODULE_PLTS > + if (!new) { > + struct module *mod = rec->arch.mod; > + > + if (mod) { > + aaddr = get_module_plt(mod, ip, aaddr); > + new = ftrace_call_replace(ip, aaddr); > + } > + } > +#endif > > return ftrace_modify_code(rec->ip, old, new, true); > } > @@ -199,20 +224,39 @@ int ftrace_make_nop(struct module *mod, > unsigned long new; > int ret; > > - old = ftrace_call_replace(ip, adjust_address(rec, addr)); > - new = ftrace_nop_replace(rec); > - ret = ftrace_modify_code(ip, old, new, true); > +#ifdef CONFIG_ARM_MODULE_PLTS > + /* mod is only supplied during module loading */ > + if (!mod) > + mod = rec->arch.mod; > + else > + rec->arch.mod = mod; > +#endif > > -#ifdef CONFIG_OLD_MCOUNT > - if (ret == -EINVAL && addr == MCOUNT_ADDR) { > - rec->arch.old_mcount = true; > + for (;;) { > + unsigned long aaddr = adjust_address(rec, addr); > + > + old = ftrace_call_replace(ip, aaddr); > + > +#ifdef CONFIG_ARM_MODULE_PLTS > + if (!old && mod) { > + aaddr = get_module_plt(mod, ip, aaddr); > + old = ftrace_call_replace(ip, aaddr); > + } > +#endif > > - old = ftrace_call_replace(ip, adjust_address(rec, addr)); > new = ftrace_nop_replace(rec); > ret = ftrace_modify_code(ip, old, new, true); > - } > + > +#ifdef CONFIG_OLD_MCOUNT > + if (ret == -EINVAL && !rec->arch.old_mcount) { > + rec->arch.old_mcount = true; > + continue; > + } > #endif > > + break; > + } > + > return ret; > } > > diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c > index f272711..a216256 100644 > --- a/arch/arm/kernel/module-plts.c > +++ b/arch/arm/kernel/module-plts.c > @@ -7,6 +7,7 @@ > */ > > #include <linux/elf.h> > +#include <linux/ftrace.h> > #include <linux/kernel.h> > #include <linux/module.h> > #include <linux/sort.h> > @@ -22,6 +23,15 @@ > (PLT_ENT_STRIDE - 8)) > #endif > > +static u32 fixed_plts[] = { > + FTRACE_ADDR, > + MCOUNT_ADDR, > +#ifdef CONFIG_OLD_MCOUNT > + (unsigned long)ftrace_caller_old, > + (unsigned long)mcount, > +#endif > +}; > + Do we need this stuff in the PLT loader if ftrace is disabled? > static bool in_init(const struct module *mod, unsigned long loc) > { > return loc - (u32)mod->init_layout.base < mod->init_layout.size; > @@ -31,26 +41,43 @@ u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val) > { > struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core : > &mod->arch.init; > + int idx; > + struct plt_entries *plt; > + > + /* Pre-allocate entries in the first plt */ > + if (!pltsec->plt_count) { > + plt = (struct plt_entries *)pltsec->plt->sh_addr; > + for (idx = 0; idx < ARRAY_SIZE(plt->ldr); ++idx) > + plt->ldr[idx] = PLT_ENT_LDR; > + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts)); > + pltsec->plt_count = ARRAY_SIZE(fixed_plts); > + /* > + * cache the address, > + * ELF header is available only during module load > + */ > + pltsec->plt_ent = plt; > + } > + plt = pltsec->plt_ent; > > - struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr; > - int idx = 0; > + idx = ARRAY_SIZE(fixed_plts); > + while (idx) > + if (plt->lit[--idx] == val) > + return (u32)&plt->ldr[idx]; > Same here. > /* > * Look for an existing entry pointing to 'val'. Given that the > * relocations are sorted, this will be the last entry we allocated. > * (if one exists). > */ > - if (pltsec->plt_count > 0) { > - plt += (pltsec->plt_count - 1) / PLT_ENT_COUNT; > - idx = (pltsec->plt_count - 1) % PLT_ENT_COUNT; > + plt += (pltsec->plt_count - 1) / PLT_ENT_COUNT; > + idx = (pltsec->plt_count - 1) % PLT_ENT_COUNT; > > - if (plt->lit[idx] == val) > - return (u32)&plt->ldr[idx]; > + if (plt->lit[idx] == val) > + return (u32)&plt->ldr[idx]; > > - idx = (idx + 1) % PLT_ENT_COUNT; > - if (!idx) > - plt++; > - } > + idx = (idx + 1) % PLT_ENT_COUNT; > + if (!idx) > + plt++; > > pltsec->plt_count++; > BUG_ON(pltsec->plt_count * PLT_ENT_SIZE > pltsec->plt->sh_size); > @@ -182,8 +209,8 @@ static unsigned int count_plts(const Elf32_Sym *syms, Elf32_Addr base, > int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, > char *secstrings, struct module *mod) > { > - unsigned long core_plts = 0; > - unsigned long init_plts = 0; > + unsigned long core_plts = ARRAY_SIZE(fixed_plts); > + unsigned long init_plts = ARRAY_SIZE(fixed_plts); > Elf32_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; > Elf32_Sym *syms = NULL; > > -- > 2.4.6 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hello Ard! On 09/03/18 09:50, Ard Biesheuvel wrote: >> +static u32 fixed_plts[] = { >> + FTRACE_ADDR, >> + MCOUNT_ADDR, >> +#ifdef CONFIG_OLD_MCOUNT >> + (unsigned long)ftrace_caller_old, >> + (unsigned long)mcount, >> +#endif >> +}; >> + > Do we need this stuff in the PLT loader if ftrace is disabled? You are right, it probably would not even build w/o FTRACE. I'll fix it, thanks for looking into this! >> static bool in_init(const struct module *mod, unsigned long loc) >> { >> return loc - (u32)mod->init_layout.base < mod->init_layout.size; >> @@ -31,26 +41,43 @@ u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val) >> { >> struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core : >> &mod->arch.init; >> + int idx; >> + struct plt_entries *plt; >> + >> + /* Pre-allocate entries in the first plt */ >> + if (!pltsec->plt_count) { >> + plt = (struct plt_entries *)pltsec->plt->sh_addr; >> + for (idx = 0; idx < ARRAY_SIZE(plt->ldr); ++idx) >> + plt->ldr[idx] = PLT_ENT_LDR; >> + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts)); >> + pltsec->plt_count = ARRAY_SIZE(fixed_plts); >> + /* >> + * cache the address, >> + * ELF header is available only during module load >> + */ >> + pltsec->plt_ent = plt; >> + } >> + plt = pltsec->plt_ent; >> >> - struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr; >> - int idx = 0; >> + idx = ARRAY_SIZE(fixed_plts); >> + while (idx) >> + if (plt->lit[--idx] == val) >> + return (u32)&plt->ldr[idx]; >> > Same here.
On 9 March 2018 at 08:54, Alexander Sverdlin <alexander.sverdlin@nokia.com> wrote: > Hello Ard! > > On 09/03/18 09:50, Ard Biesheuvel wrote: >>> +static u32 fixed_plts[] = { >>> + FTRACE_ADDR, >>> + MCOUNT_ADDR, >>> +#ifdef CONFIG_OLD_MCOUNT >>> + (unsigned long)ftrace_caller_old, >>> + (unsigned long)mcount, >>> +#endif >>> +}; >>> + >> Do we need this stuff in the PLT loader if ftrace is disabled? > > You are right, it probably would not even build w/o FTRACE. > I'll fix it, thanks for looking into this! > Also, perhaps you can make the array const (after you put #ifdef's around all entries) >>> static bool in_init(const struct module *mod, unsigned long loc) >>> { >>> return loc - (u32)mod->init_layout.base < mod->init_layout.size; >>> @@ -31,26 +41,43 @@ u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val) >>> { >>> struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core : >>> &mod->arch.init; >>> + int idx; >>> + struct plt_entries *plt; >>> + >>> + /* Pre-allocate entries in the first plt */ >>> + if (!pltsec->plt_count) { >>> + plt = (struct plt_entries *)pltsec->plt->sh_addr; >>> + for (idx = 0; idx < ARRAY_SIZE(plt->ldr); ++idx) >>> + plt->ldr[idx] = PLT_ENT_LDR; >>> + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts)); >>> + pltsec->plt_count = ARRAY_SIZE(fixed_plts); >>> + /* >>> + * cache the address, >>> + * ELF header is available only during module load >>> + */ >>> + pltsec->plt_ent = plt; >>> + } >>> + plt = pltsec->plt_ent; >>> >>> - struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr; >>> - int idx = 0; >>> + idx = ARRAY_SIZE(fixed_plts); >>> + while (idx) >>> + if (plt->lit[--idx] == val) >>> + return (u32)&plt->ldr[idx]; >>> ... and put all this handling in a helper function that only gets called if ARRAY_SIZE() > 0 AFAICT, that should allow you to leave the rest unchanged.
diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index 9e842ff..faeb6b1 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -19,6 +19,9 @@ struct dyn_arch_ftrace { #ifdef CONFIG_OLD_MCOUNT bool old_mcount; #endif +#ifdef CONFIG_ARM_MODULE_PLTS + struct module *mod; +#endif }; static inline unsigned long ftrace_call_adjust(unsigned long addr) diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h index 6996405..e3d7a51 100644 --- a/arch/arm/include/asm/module.h +++ b/arch/arm/include/asm/module.h @@ -30,6 +30,7 @@ struct plt_entries { struct mod_plt_sec { struct elf32_shdr *plt; + struct plt_entries *plt_ent; int plt_count; }; diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 5617932..b55355f 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -98,6 +98,19 @@ int ftrace_arch_code_modify_post_process(void) static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) { + s32 offset = addr - pc; + s32 blim = 0xfe000008; + s32 flim = 0x02000004; + + if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) { + blim = 0xff000004; + flim = 0x01000002; + } + + if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && + (offset < blim || offset > flim)) + return 0; + return arm_gen_branch_link(pc, addr); } @@ -166,10 +179,22 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long new, old; unsigned long ip = rec->ip; + unsigned long aaddr = adjust_address(rec, addr); old = ftrace_nop_replace(rec); - new = ftrace_call_replace(ip, adjust_address(rec, addr)); + new = ftrace_call_replace(ip, aaddr); + +#ifdef CONFIG_ARM_MODULE_PLTS + if (!new) { + struct module *mod = rec->arch.mod; + + if (mod) { + aaddr = get_module_plt(mod, ip, aaddr); + new = ftrace_call_replace(ip, aaddr); + } + } +#endif return ftrace_modify_code(rec->ip, old, new, true); } @@ -199,20 +224,39 @@ int ftrace_make_nop(struct module *mod, unsigned long new; int ret; - old = ftrace_call_replace(ip, adjust_address(rec, addr)); - new = ftrace_nop_replace(rec); - ret = ftrace_modify_code(ip, old, new, true); +#ifdef CONFIG_ARM_MODULE_PLTS + /* mod is only supplied during module loading */ + if (!mod) + mod = rec->arch.mod; + else + rec->arch.mod = mod; +#endif -#ifdef CONFIG_OLD_MCOUNT - if (ret == -EINVAL && addr == MCOUNT_ADDR) { - rec->arch.old_mcount = true; + for (;;) { + unsigned long aaddr = adjust_address(rec, addr); + + old = ftrace_call_replace(ip, aaddr); + +#ifdef CONFIG_ARM_MODULE_PLTS + if (!old && mod) { + aaddr = get_module_plt(mod, ip, aaddr); + old = ftrace_call_replace(ip, aaddr); + } +#endif - old = ftrace_call_replace(ip, adjust_address(rec, addr)); new = ftrace_nop_replace(rec); ret = ftrace_modify_code(ip, old, new, true); - } + +#ifdef CONFIG_OLD_MCOUNT + if (ret == -EINVAL && !rec->arch.old_mcount) { + rec->arch.old_mcount = true; + continue; + } #endif + break; + } + return ret; } diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c index f272711..a216256 100644 --- a/arch/arm/kernel/module-plts.c +++ b/arch/arm/kernel/module-plts.c @@ -7,6 +7,7 @@ */ #include <linux/elf.h> +#include <linux/ftrace.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sort.h> @@ -22,6 +23,15 @@ (PLT_ENT_STRIDE - 8)) #endif +static u32 fixed_plts[] = { + FTRACE_ADDR, + MCOUNT_ADDR, +#ifdef CONFIG_OLD_MCOUNT + (unsigned long)ftrace_caller_old, + (unsigned long)mcount, +#endif +}; + static bool in_init(const struct module *mod, unsigned long loc) { return loc - (u32)mod->init_layout.base < mod->init_layout.size; @@ -31,26 +41,43 @@ u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val) { struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core : &mod->arch.init; + int idx; + struct plt_entries *plt; + + /* Pre-allocate entries in the first plt */ + if (!pltsec->plt_count) { + plt = (struct plt_entries *)pltsec->plt->sh_addr; + for (idx = 0; idx < ARRAY_SIZE(plt->ldr); ++idx) + plt->ldr[idx] = PLT_ENT_LDR; + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts)); + pltsec->plt_count = ARRAY_SIZE(fixed_plts); + /* + * cache the address, + * ELF header is available only during module load + */ + pltsec->plt_ent = plt; + } + plt = pltsec->plt_ent; - struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr; - int idx = 0; + idx = ARRAY_SIZE(fixed_plts); + while (idx) + if (plt->lit[--idx] == val) + return (u32)&plt->ldr[idx]; /* * Look for an existing entry pointing to 'val'. Given that the * relocations are sorted, this will be the last entry we allocated. * (if one exists). */ - if (pltsec->plt_count > 0) { - plt += (pltsec->plt_count - 1) / PLT_ENT_COUNT; - idx = (pltsec->plt_count - 1) % PLT_ENT_COUNT; + plt += (pltsec->plt_count - 1) / PLT_ENT_COUNT; + idx = (pltsec->plt_count - 1) % PLT_ENT_COUNT; - if (plt->lit[idx] == val) - return (u32)&plt->ldr[idx]; + if (plt->lit[idx] == val) + return (u32)&plt->ldr[idx]; - idx = (idx + 1) % PLT_ENT_COUNT; - if (!idx) - plt++; - } + idx = (idx + 1) % PLT_ENT_COUNT; + if (!idx) + plt++; pltsec->plt_count++; BUG_ON(pltsec->plt_count * PLT_ENT_SIZE > pltsec->plt->sh_size); @@ -182,8 +209,8 @@ static unsigned int count_plts(const Elf32_Sym *syms, Elf32_Addr base, int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { - unsigned long core_plts = 0; - unsigned long init_plts = 0; + unsigned long core_plts = ARRAY_SIZE(fixed_plts); + unsigned long init_plts = ARRAY_SIZE(fixed_plts); Elf32_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; Elf32_Sym *syms = NULL;
Teach ftrace_make_call() and ftrace_make_nop() about PLTs. Teach PLT code about FTRACE and all its callbacks. Otherwise the following might happen: ------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../arch/arm/kernel/insn.c:14 __arm_gen_branch+0x83/0x8c() ... Hardware name: LSI Axxia AXM55XX [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) [<c03218f3>] (warn_slowpath_null) from [<c03143cf>] (__arm_gen_branch+0x83/0x8c) [<c03143cf>] (__arm_gen_branch) from [<c0314337>] (ftrace_make_nop+0xf/0x24) [<c0314337>] (ftrace_make_nop) from [<c038ebcb>] (ftrace_process_locs+0x27b/0x3e8) [<c038ebcb>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcc ]--- ------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1b1/0x234() ... Hardware name: LSI Axxia AXM55XX [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) [<c03218f3>] (warn_slowpath_null) from [<c038e87d>] (ftrace_bug+0x1b1/0x234) [<c038e87d>] (ftrace_bug) from [<c038ebd5>] (ftrace_process_locs+0x285/0x3e8) [<c038ebd5>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcd ]--- ftrace failed to modify [<e9ef7006>] 0xe9ef7006 actual: 02:f0:3b:fa ftrace record flags: 0 (0) expected tramp: c0314265 Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> --- arch/arm/include/asm/ftrace.h | 3 +++ arch/arm/include/asm/module.h | 1 + arch/arm/kernel/ftrace.c | 62 ++++++++++++++++++++++++++++++++++++------- arch/arm/kernel/module-plts.c | 53 +++++++++++++++++++++++++++--------- 4 files changed, 97 insertions(+), 22 deletions(-)