From efe18f768714f969994ae7cdc6c2a8e273186e6d Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Thu, 27 Jun 2019 00:08:01 +0530 Subject: recordmcount: Fix spurious mcount entries on powerpc [ Upstream commit 80e5302e4bc85a6b685b7668c36c6487b5f90e9a ] An impending change to enable HAVE_C_RECORDMCOUNT on powerpc leads to warnings such as the following: # modprobe kprobe_example ftrace-powerpc: Not expected bl: opcode is 3c4c0001 WARNING: CPU: 0 PID: 227 at kernel/trace/ftrace.c:2001 ftrace_bug+0x90/0x318 Modules linked in: CPU: 0 PID: 227 Comm: modprobe Not tainted 5.2.0-rc6-00678-g1c329100b942 #2 NIP: c000000000264318 LR: c00000000025d694 CTR: c000000000f5cd30 REGS: c000000001f2b7b0 TRAP: 0700 Not tainted (5.2.0-rc6-00678-g1c329100b942) MSR: 900000010282b033 CR: 28228222 XER: 00000000 CFAR: c0000000002642fc IRQMASK: 0 NIP [c000000000264318] ftrace_bug+0x90/0x318 LR [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 Call Trace: [c000000001f2ba40] [0000000000000004] 0x4 (unreliable) [c000000001f2bad0] [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 [c000000001f2bb90] [c00000000020ff10] load_module+0x25b0/0x30c0 [c000000001f2bd00] [c000000000210cb0] sys_finit_module+0xc0/0x130 [c000000001f2be20] [c00000000000bda4] system_call+0x5c/0x70 Instruction dump: 419e0018 2f83ffff 419e00bc 2f83ffea 409e00cc 4800001c 0fe00000 3c62ff96 39000001 39400000 386386d0 480000c4 <0fe00000> 3ce20003 39000001 3c62ff96 ---[ end trace 4c438d5cebf78381 ]--- ftrace failed to modify [] 0xc0080000012a0008 actual: 01:00:4c:3c Initializing ftrace call sites ftrace record flags: 2000000 (0) expected tramp: c00000000006af4c Looking at the relocation records in __mcount_loc shows a few spurious entries: RELOCATION RECORDS FOR [__mcount_loc]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_ADDR64 .text.unlikely+0x0000000000000008 0000000000000008 R_PPC64_ADDR64 .text.unlikely+0x0000000000000014 0000000000000010 R_PPC64_ADDR64 .text.unlikely+0x0000000000000060 0000000000000018 R_PPC64_ADDR64 .text.unlikely+0x00000000000000b4 0000000000000020 R_PPC64_ADDR64 .init.text+0x0000000000000008 0000000000000028 R_PPC64_ADDR64 .init.text+0x0000000000000014 The first entry in each section is incorrect. Looking at the relocation records, the spurious entries correspond to the R_PPC64_ENTRY records: RELOCATION RECORDS FOR [.text.unlikely]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_REL64 .TOC.-0x0000000000000008 0000000000000008 R_PPC64_ENTRY *ABS* 0000000000000014 R_PPC64_REL24 _mcount The problem is that we are not validating the return value from get_mcountsym() in sift_rel_mcount(). With this entry, mcountsym is 0, but Elf_r_sym(relp) also ends up being 0. Fix this by ensuring mcountsym is valid before processing the entry. Signed-off-by: Naveen N. Rao Acked-by: Steven Rostedt (VMware) Tested-by: Satheesh Rajendran Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- scripts/recordmcount.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h index b9897e2be404..04151ede8043 100644 --- a/scripts/recordmcount.h +++ b/scripts/recordmcount.h @@ -326,7 +326,8 @@ static uint_t *sift_rel_mcount(uint_t *mlocp, if (!mcountsym) mcountsym = get_mcountsym(sym0, relp, str0); - if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) { + if (mcountsym && mcountsym == Elf_r_sym(relp) && + !is_fake_mcount(relp)) { uint_t const addend = _w(_w(relp->r_offset) - recval + mcount_adjust); mrelp->r_offset = _w(offbase -- cgit v1.2.3 From 76f095a6313fa7710eb82157f606417ebef29113 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Fri, 28 Jun 2019 19:22:47 +0200 Subject: kallsyms: exclude kasan local symbols on s390 [ Upstream commit 33177f01ca3fe550146bb9001bec2fd806b2f40c ] gcc asan instrumentation emits the following sequence to store frame pc when the kernel is built with CONFIG_RELOCATABLE: debug/vsprintf.s: .section .data.rel.ro.local,"aw" .align 8 .LC3: .quad .LASANPC4826@GOTOFF .text .align 8 .type number, @function number: .LASANPC4826: and in case reloc is issued for LASANPC label it also gets into .symtab with the same address as actual function symbol: $ nm -n vmlinux | grep 0000000001397150 0000000001397150 t .LASANPC4826 0000000001397150 t number In the end kernel backtraces are almost unreadable: [ 143.748476] Call Trace: [ 143.748484] ([<000000002da3e62c>] .LASANPC2671+0x114/0x190) [ 143.748492] [<000000002eca1a58>] .LASANPC2612+0x110/0x160 [ 143.748502] [<000000002de9d830>] print_address_description+0x80/0x3b0 [ 143.748511] [<000000002de9dd64>] __kasan_report+0x15c/0x1c8 [ 143.748521] [<000000002ecb56d4>] strrchr+0x34/0x60 [ 143.748534] [<000003ff800a9a40>] kasan_strings+0xb0/0x148 [test_kasan] [ 143.748547] [<000003ff800a9bba>] kmalloc_tests_init+0xe2/0x528 [test_kasan] [ 143.748555] [<000000002da2117c>] .LASANPC4069+0x354/0x748 [ 143.748563] [<000000002dbfbb16>] do_init_module+0x136/0x3b0 [ 143.748571] [<000000002dbff3f4>] .LASANPC3191+0x2164/0x25d0 [ 143.748580] [<000000002dbffc4c>] .LASANPC3196+0x184/0x1b8 [ 143.748587] [<000000002ecdf2ec>] system_call+0xd8/0x2d8 Since LASANPC labels are not even unique and get into .symtab only due to relocs filter them out in kallsyms. Signed-off-by: Vasily Gorbik Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin --- scripts/kallsyms.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'scripts') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 8fa81e84e295..d117c68d1607 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -158,6 +158,9 @@ static int read_symbol(FILE *in, struct sym_entry *s) /* exclude debugging symbols */ else if (stype == 'N') return -1; + /* exclude s390 kasan local symbols */ + else if (!strncmp(sym, ".LASANPC", 8)) + return -1; /* include the type field in the symbol name, so that it gets * compressed together */ -- cgit v1.2.3