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Tue, 15 Mar 2022 09:51:29 +0000 (GMT) Received: from epsmgms1p2.samsung.com (unknown [182.195.42.42]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20220315095129epsmtrp1ef8bfabda16605dd0b4bf28c2125d786~chRU1nckh0754907549epsmtrp1g; Tue, 15 Mar 2022 09:51:29 +0000 (GMT) X-AuditID: b6c32a4b-723ff700000015d6-c8-623062b1bd63 Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p2.samsung.com (Symantec Messaging Gateway) with SMTP id 7B.2D.03370.1A160326; Tue, 15 Mar 2022 18:51:29 +0900 (KST) Received: from localhost.localdomain (unknown [107.109.224.44]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20220315095126epsmtip13d1a36e1cf00a4e8c27711ff0ba44c8c~chRSH3aU92135621356epsmtip1e; Tue, 15 Mar 2022 09:51:26 +0000 (GMT) From: Maninder Singh To: mcgrof@kernel.org, pmladek@suse.com, rostedt@goodmis.org, senozhatsky@chromium.org, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, akpm@linux-foundation.org, wangkefeng.wang@huawei.com Cc: v.narang@samsung.com, swboyd@chromium.org, ojeda@kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, avimalin@gmail.com, atomlin@redhat.com, Maninder Singh Subject: [PATCH v2] kallsyms: enhance %pS/s/b printing when KALLSYSMS is disabled Date: Tue, 15 Mar 2022 15:21:12 +0530 Message-Id: <20220315095112.439580-1-maninder1.s@samsung.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrBKsWRmVeSWpSXmKPExsWy7bCmhu7GJIMkg0t7FSzmrF/DZtHbNJ3J 4sj8NawWDw5eZ7e4vGsOm0XD7O+sFo9nzWOzODy/jcXixoSnjBYr5y9ntPj/+Curxb6OB0wW uzcuYrM4fucpk8Whk3MZLRo/32d0EPCY3XCRxWPnrLvsHi37bgGJI29ZPTat6mTzODHjN4vH vJOBHhe6sj3e77vK5tG3ZRWjx/otV1k8Pm+SC+CJ4rJJSc3JLEst0rdL4Mo48PA1Y8EPz4qD n3+wNTDes+li5OSQEDCR2LvsPFsXIxeHkMBuRonFHzcxQTifGCXOHvrIDOF8ZpRYv/kIO0zL v/OLmUFsIYFdjBIrV0RAFH1hlLgwqRWsiE1AT2LVrj0sIAkRgQuMEldu7QHrYBa4wijxaBoX iC0sECyxbuYKVhCbRUBVYtK91WA2r4CtRGPjeiaIbfISMy99Z4eIC0qcnPmEBWKOvETz1tnM EDV7OCTuLc2GsF0k7l7cB9UrLPHq+Baoq6UkXva3sYMcJCHQzSixofsYC4Qzg1Hi88GrjBBV 9hJPLi4EuoIDaIOmxPpd+hBhWYmpp9YxQSzmk+j9/QRqAa/EjnkwtqpEy80NrBC2tMTnjx9Z IGwPiWkb+qDBFSux6vgqpgmM8rOQ/DMLyT+zEDYvYGRexSiZWlCcm55abFpgnJdarlecmFtc mpeul5yfu4kRnPi0vHcwPnrwQe8QIxMH4yFGCQ5mJRHeMy/0k4R4UxIrq1KL8uOLSnNSiw8x SnOwKInznkrfkCgkkJ5YkpqdmlqQWgSTZeLglGpg2u99Ys6VUy9OVMt80jls15f4xYE9i8v0 nP/yu3EHlrE/39/WohH7o/6Zt5ad3YeKRXPnWPrwKjYv2Cs++53Spk1NSvpnnpZ0quUo2Xm+ WLPzhg/zAtVE1ZLFPkXu/q93F5kZ2iqqX05cfv7l5tL8zTO77k6IO8u91GXxt/Lq1sIFPb/e x26pePci7mzwTv2VPkF3fq+4s1s0pZ67gX377K07NaLEpMO49NIiTQ32nghgkpjyS75l623/ jw9eyE4UnD/Farnddn7bWbdzaq50G8XMUDi0+yNbhWTyykijFKNY2UNMHUpJPIsPvK/sTE2V Sr+xXrH+ntv+f2U/char3m1d2P86lPVq6u2d8t/5lFiKMxINtZiLihMBiTR8vesDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrLLMWRmVeSWpSXmKPExsWy7bCSnO7CRIMkg02TdSzmrF/DZtHbNJ3J 4sj8NawWDw5eZ7e4vGsOm0XD7O+sFo9nzWOzODy/jcXixoSnjBYr5y9ntPj/+Curxb6OB0wW uzcuYrM4fucpk8Whk3MZLRo/32d0EPCY3XCRxWPnrLvsHi37bgGJI29ZPTat6mTzODHjN4vH vJOBHhe6sj3e77vK5tG3ZRWjx/otV1k8Pm+SC+CJ4rJJSc3JLEst0rdL4Mo48PA1Y8EPz4qD n3+wNTDes+li5OSQEDCR+Hd+MTOILSSwg1GiZ00wRFxa4ue/9ywQtrDEyn/P2SFqPjFKfDyj CWKzCehJrNq1B6iGi0NE4AajxOKFncwgDrPAHUaJb5+PgnUICwRKnJv0EGwDi4CqxKR7q1lB bF4BW4nGxvVMEBvkJWZe+s4OEReUODnzCdhmZqB489bZzBMY+WYhSc1CklrAyLSKUTK1oDg3 PbfYsMAoL7Vcrzgxt7g0L10vOT93EyM4hrS0djDuWfVB7xAjEwfjIUYJDmYlEd4zL/SThHhT EiurUovy44tKc1KLDzFKc7AoifNe6DoZLySQnliSmp2aWpBaBJNl4uCUamAq3P9os7nf1PCS 3/Lp/cK1K7O8Tj2M++i4v+Z67cXXWj7R1ldc2c2kOJ6ZXg4+VNt7huFWVPuqRH63A8fm/lmu ZWt2SeBIwJn3inffK70qf1xVHJg++ZvZuSOLtzK4z3K26vKddfTbPF6VYFPxlc/Z5CYsFHYr 2afxb0Uhr2m/vWJ9meelpLtf5G45bWr+dUjczzQorlNY5LN7NauDCjdDcsLhduZ7Ie9ve2yr thU/1F7nbqoS9T5eTEnSeOcZdxum+LDEQ1eKuT2z+xpjTp5i0eboz211OupvrsCXNomTuz8r KEfnxOvfUqpPmc7OOrPUfuXj+G4LqS/xAeKee5isbruLPU97v8+Ye3OQEktxRqKhFnNRcSIA 2+WnQBADAAA= X-CMS-MailID: 20220315095129epcas5p230b94ea10517d148c9cae0669229b0fc X-Msg-Generator: CA X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P X-CMS-RootMailID: 20220315095129epcas5p230b94ea10517d148c9cae0669229b0fc References: Precedence: bulk List-ID: print module information when KALLSYMS is disabled. No change for %pB, as it needs to know symbol name to adjust address value which can't be done without KALLSYMS. (A) original output with KALLSYMS: [8.842129] ps function_1 [crash] [8.842735] pS function_1+0x4/0x2c [crash] [8.842890] pSb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3] [8.843175] pB function_1+0x4/0x2c [crash] [8.843362] pBb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3] (B) original output without KALLSYMS: [12.487424] ps 0xffff800000eb008c [12.487598] pS 0xffff800000eb008c [12.487723] pSb 0xffff800000eb008c [12.487850] pB 0xffff800000eb008c [12.487967] pBb 0xffff800000eb008c (C) With patched kernel without KALLSYMS: [7.870286] ps 0xffff800000f2008c [crash] // similar to original [7.870716] pS 0x(____ptrval____)+0x8c [crash] // base address hashed and offset is without hash [7.871025] pSb 0x(____ptrval____)+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca] [7.871321] pB 0x(____ptrval____)+0x8c [crash] [7.871512] pBb 0x(____ptrval____)+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca] [7.872191] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 with disable hashing: [8.563916] ps 0xffff800000f2008c [crash] [8.564574] pS 0xffff800000f20000+0x8c [crash] [8.564749] pSb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca] [8.565008] pB 0xffff800000f20000+0x8c [crash] [8.565154] pBb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca] Suggested-by: Petr Mladek Co-developed-by: Vaneet Narang Signed-off-by: Vaneet Narang Signed-off-by: Maninder Singh --- v1->v2: hash base address of module, change *fmt to fmt[0] and removed copy paste. include/linux/kallsyms.h | 2 + include/linux/module.h | 22 +++++++++++ kernel/kallsyms.c | 26 ++++++------- kernel/module.c | 4 +- lib/vsprintf.c | 84 +++++++++++++++++++++++++++++++++------- 5 files changed, 109 insertions(+), 29 deletions(-) diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index e5ad6e31697d..c24fa627ab6e 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -89,6 +89,8 @@ extern int sprint_symbol_build_id(char *buffer, unsigned long address); extern int sprint_symbol_no_offset(char *buffer, unsigned long address); extern int sprint_backtrace(char *buffer, unsigned long address); extern int sprint_backtrace_build_id(char *buffer, unsigned long address); +extern int sprint_kallsym_common(char *buffer, unsigned long address, int build_id, + int backtrace, int symbol); int lookup_symbol_name(unsigned long addr, char *symname); int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name); diff --git a/include/linux/module.h b/include/linux/module.h index 1e135fd5c076..26a49e663351 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -678,6 +678,22 @@ static inline bool is_livepatch_module(struct module *mod) bool is_module_sig_enforced(void); void set_module_sig_enforced(void); +static inline int fill_name_build_id(char *buffer, char *modname, + int add_buildid, const unsigned char *buildid, + int len) +{ + len += sprintf(buffer + len, " [%s", modname); +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) + if (add_buildid && buildid) { + /* build ID should match length of sprintf */ + static_assert(sizeof(typeof_member(struct module, build_id)) == 20); + len += sprintf(buffer + len, " %20phN", buildid); + } +#endif + len += sprintf(buffer + len, "]"); + + return len; +} #else /* !CONFIG_MODULES... */ static inline struct module *__module_address(unsigned long addr) @@ -818,6 +834,12 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr) return ptr; } +static inline int fill_name_build_id(char *buffer, char *modname, + int add_buildid, const unsigned char *buildid, + int len) +{ + return 0; +} #endif /* CONFIG_MODULES */ #ifdef CONFIG_SYSFS diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 57213e1d2349..cdbcaf86252a 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -479,19 +479,8 @@ static int __sprint_symbol(char *buffer, unsigned long address, if (add_offset) len += sprintf(buffer + len, "+%#lx/%#lx", offset, size); - if (modname) { - len += sprintf(buffer + len, " [%s", modname); -#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) - if (add_buildid && buildid) { - /* build ID should match length of sprintf */ -#if IS_ENABLED(CONFIG_MODULES) - static_assert(sizeof(typeof_member(struct module, build_id)) == 20); -#endif - len += sprintf(buffer + len, " %20phN", buildid); - } -#endif - len += sprintf(buffer + len, "]"); - } + if (modname) + len += fill_name_build_id(buffer, modname, add_buildid, buildid, len); return len; } @@ -586,6 +575,17 @@ int sprint_backtrace_build_id(char *buffer, unsigned long address) return __sprint_symbol(buffer, address, -1, 1, 1); } +int sprint_kallsym_common(char *buffer, unsigned long address, int build_id, + int backtrace, int symbol) +{ + if (backtrace) + return __sprint_symbol(buffer, address, -1, 1, build_id); + else if (symbol) + return __sprint_symbol(buffer, address, 0, 1, build_id); + else + return __sprint_symbol(buffer, address, 0, 0, 0); +} + /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ struct kallsym_iter { loff_t pos; diff --git a/kernel/module.c b/kernel/module.c index 6cea788fd965..5756d31a024b 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1465,12 +1465,10 @@ resolve_symbol_wait(struct module *mod, return ksym; } -#ifdef CONFIG_KALLSYMS static inline bool sect_empty(const Elf_Shdr *sect) { return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; } -#endif /* * /sys/module/foo/sections stuff @@ -2799,7 +2797,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) } #endif /* CONFIG_KALLSYMS */ -#if IS_ENABLED(CONFIG_KALLSYMS) && IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) static void init_build_id(struct module *mod, const struct load_info *info) { const Elf_Shdr *sechdr; diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 7adb8fd4d804..064b0cc45a37 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1000,33 +1000,91 @@ char *bdev_name(char *buf, char *end, struct block_device *bdev, } #endif +#if !defined(CONFIG_KALLSYMS) && defined(CONFIG_MODULES) +static int sprint_module_info(char *buf, char *end, unsigned long value, + const char *fmt, int modbuildid, int backtrace, int symbol) +{ + struct module *mod; + unsigned long offset = 0; + unsigned long base; + char *modname; + int len; + const unsigned char *buildid = NULL; + + if (is_ksym_addr(value)) + return 0; + + if (backtrace || symbol) + offset = 1; + + preempt_disable(); + mod = __module_address(value); + if (mod) { + modname = mod->name; +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) + if (modbuildid) + buildid = mod->build_id; +#endif + if (offset) { + base = (unsigned long)mod->core_layout.base; + offset = value - base; + } + } + + preempt_enable(); + if (!mod) + return 0; + + /* address belongs to module */ + if (offset) + len = sprintf(buf, "0x%p+0x%lx", (void *)base, offset); + else + len = sprintf(buf, "0x%lx", (void *)value); + + len += fill_name_build_id(buf, modname, modbuildid, buildid, len); + return len; +} +#else +static inline int sprint_module_info(char *buf, char *end, unsigned long value, + const char *fmt) +{ + return 0; +} +#endif + static noinline_for_stack char *symbol_string(char *buf, char *end, void *ptr, struct printf_spec spec, const char *fmt) { unsigned long value; -#ifdef CONFIG_KALLSYMS char sym[KSYM_SYMBOL_LEN]; -#endif + int backtrace = 0, symbol = 0, build_id = 0; if (fmt[1] == 'R') ptr = __builtin_extract_return_addr(ptr); value = (unsigned long)ptr; -#ifdef CONFIG_KALLSYMS - if (*fmt == 'B' && fmt[1] == 'b') - sprint_backtrace_build_id(sym, value); - else if (*fmt == 'B') - sprint_backtrace(sym, value); - else if (*fmt == 'S' && (fmt[1] == 'b' || (fmt[1] == 'R' && fmt[2] == 'b'))) - sprint_symbol_build_id(sym, value); - else if (*fmt != 's') - sprint_symbol(sym, value); - else - sprint_symbol_no_offset(sym, value); + if (fmt[0] == 'B' && fmt[1] == 'b') { + backtrace = 1; + build_id = 1; + } else if (fmt[0] == 'B') + backtrace = 1; + else if (fmt[0] == 'S' && (fmt[1] == 'b' || (fmt[1] == 'R' && fmt[2] == 'b'))) { + symbol = 1; + build_id = 1; + } else if (fmt[0] != 's') + symbol = 1; + else { + /* Do Nothing, no offset */ + } +#ifdef CONFIG_KALLSYMS + sprint_kallsym_common(sym, value, build_id, backtrace, symbol); return string_nocheck(buf, end, sym, spec); #else + if (sprint_module_info(sym, end, value, fmt, build_id, backtrace, symbol)) + return string_nocheck(buf, end, sym, spec); + return special_hex_number(buf, end, value, sizeof(void *)); #endif }