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![Mukesh Ojha](/assets/img/avatar_default.png)
Currently, in clang version of gcov code when module is getting removed
gcov_info_add() incorrectly adds the sfn_ptr->counter to all the
dst->functions and it result in the kernel panic in below crash report.
Fix this by properly handling it.
[ 8.899094][ T599] Unable to handle kernel write to read-only memory at virtual address ffffff80461cc000
[ 8.899100][ T599] Mem abort info:
[ 8.899102][ T599] ESR = 0x9600004f
[ 8.899103][ T599] EC = 0x25: DABT (current EL), IL = 32 bits
[ 8.899105][ T599] SET = 0, FnV = 0
[ 8.899107][ T599] EA = 0, S1PTW = 0
[ 8.899108][ T599] FSC = 0x0f: level 3 permission fault
[ 8.899110][ T599] Data abort info:
[ 8.899111][ T599] ISV = 0, ISS = 0x0000004f
[ 8.899113][ T599] CM = 0, WnR = 1
[ 8.899114][ T599] swapper pgtable: 4k pages, 39-bit VAs, pgdp=00000000ab8de000
[ 8.899116][ T599] [ffffff80461cc000] pgd=18000009ffcde003, p4d=18000009ffcde003, pud=18000009ffcde003, pmd=18000009ffcad003, pte=00600000c61cc787
[ 8.899124][ T599] Internal error: Oops: 9600004f [#1] PREEMPT SMP
[ 8.899265][ T599] Skip md ftrace buffer dump for: 0x1609e0
....
..,
[ 8.899544][ T599] CPU: 7 PID: 599 Comm: modprobe Tainted: G S OE 5.15.41-android13-8-g38e9b1af6bce #1
[ 8.899547][ T599] Hardware name: XXX (DT)
[ 8.899549][ T599] pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
[ 8.899551][ T599] pc : gcov_info_add+0x9c/0xb8
[ 8.899557][ T599] lr : gcov_event+0x28c/0x6b8
[ 8.899559][ T599] sp : ffffffc00e733b00
[ 8.899560][ T599] x29: ffffffc00e733b00 x28: ffffffc00e733d30 x27: ffffffe8dc297470
[ 8.899563][ T599] x26: ffffffe8dc297000 x25: ffffffe8dc297000 x24: ffffffe8dc297000
[ 8.899566][ T599] x23: ffffffe8dc0a6200 x22: ffffff880f68bf20 x21: 0000000000000000
[ 8.899569][ T599] x20: ffffff880f68bf00 x19: ffffff8801babc00 x18: ffffffc00d7f9058
[ 8.899572][ T599] x17: 0000000000088793 x16: ffffff80461cbe00 x15: 9100052952800785
[ 8.899575][ T599] x14: 0000000000000200 x13: 0000000000000041 x12: 9100052952800785
[ 8.899577][ T599] x11: ffffffe8dc297000 x10: ffffffe8dc297000 x9 : ffffff80461cbc80
[ 8.899580][ T599] x8 : ffffff8801babe80 x7 : ffffffe8dc2ec000 x6 : ffffffe8dc2ed000
[ 8.899583][ T599] x5 : 000000008020001f x4 : fffffffe2006eae0 x3 : 000000008020001f
[ 8.899586][ T599] x2 : ffffff8027c49200 x1 : ffffff8801babc20 x0 : ffffff80461cb3a0
[ 8.899589][ T599] Call trace:
[ 8.899590][ T599] gcov_info_add+0x9c/0xb8
[ 8.899592][ T599] gcov_module_notifier+0xbc/0x120
[ 8.899595][ T599] blocking_notifier_call_chain+0xa0/0x11c
[ 8.899598][ T599] do_init_module+0x2a8/0x33c
[ 8.899600][ T599] load_module+0x23cc/0x261c
[ 8.899602][ T599] __arm64_sys_finit_module+0x158/0x194
[ 8.899604][ T599] invoke_syscall+0x94/0x2bc
[ 8.899607][ T599] el0_svc_common+0x1d8/0x34c
[ 8.899609][ T599] do_el0_svc+0x40/0x54
[ 8.899611][ T599] el0_svc+0x94/0x2f0
[ 8.899613][ T599] el0t_64_sync_handler+0x88/0xec
[ 8.899615][ T599] el0t_64_sync+0x1b4/0x1b8
[ 8.899618][ T599] Code: f905f56c f86e69ec f86e6a0f 8b0c01ec (f82e6a0c)
[ 8.899620][ T599] ---[ end trace ed5218e9e5b6e2e6 ]---
Link: https://lkml.kernel.org/r/1668020497-13142-1-git-send-email-quic_mojha@quicinc.com
Fixes: e178a5beb3
("gcov: clang support")
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Tested-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org> [5.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
393 lines
10 KiB
C
393 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 Google, Inc.
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* modified from kernel/gcov/gcc_4_7.c
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*
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* LLVM uses profiling data that's deliberately similar to GCC, but has a
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* very different way of exporting that data. LLVM calls llvm_gcov_init() once
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* per module, and provides a couple of callbacks that we can use to ask for
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* more data.
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*
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* We care about the "writeout" callback, which in turn calls back into
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* compiler-rt/this module to dump all the gathered coverage data to disk:
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*
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* llvm_gcda_start_file()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* llvm_gcda_emit_function()
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* llvm_gcda_emit_arcs()
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* [... repeats for each function ...]
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* llvm_gcda_summary_info()
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* llvm_gcda_end_file()
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*
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* This design is much more stateless and unstructured than gcc's, and is
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* intended to run at process exit. This forces us to keep some local state
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* about which module we're dealing with at the moment. On the other hand, it
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* also means we don't depend as much on how LLVM represents profiling data
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* internally.
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*
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* See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
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* details on how this works, particularly GCOVProfiler::emitProfileArcs(),
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* GCOVProfiler::insertCounterWriteout(), and
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* GCOVProfiler::insertFlush().
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*/
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#define pr_fmt(fmt) "gcov: " fmt
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/printk.h>
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#include <linux/ratelimit.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include "gcov.h"
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typedef void (*llvm_gcov_callback)(void);
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struct gcov_info {
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struct list_head head;
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const char *filename;
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unsigned int version;
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u32 checksum;
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struct list_head functions;
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};
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struct gcov_fn_info {
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struct list_head head;
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u32 ident;
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u32 checksum;
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u32 cfg_checksum;
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u32 num_counters;
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u64 *counters;
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};
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static struct gcov_info *current_info;
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static LIST_HEAD(clang_gcov_list);
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void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
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{
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struct gcov_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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INIT_LIST_HEAD(&info->functions);
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mutex_lock(&gcov_lock);
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list_add_tail(&info->head, &clang_gcov_list);
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current_info = info;
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writeout();
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current_info = NULL;
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if (gcov_events_enabled)
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gcov_event(GCOV_ADD, info);
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mutex_unlock(&gcov_lock);
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}
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EXPORT_SYMBOL(llvm_gcov_init);
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void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
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{
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current_info->filename = orig_filename;
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current_info->version = version;
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current_info->checksum = checksum;
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}
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EXPORT_SYMBOL(llvm_gcda_start_file);
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void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
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{
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struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return;
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INIT_LIST_HEAD(&info->head);
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info->ident = ident;
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info->checksum = func_checksum;
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info->cfg_checksum = cfg_checksum;
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list_add_tail(&info->head, ¤t_info->functions);
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}
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EXPORT_SYMBOL(llvm_gcda_emit_function);
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void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
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{
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struct gcov_fn_info *info = list_last_entry(¤t_info->functions,
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struct gcov_fn_info, head);
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info->num_counters = num_counters;
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info->counters = counters;
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}
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EXPORT_SYMBOL(llvm_gcda_emit_arcs);
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void llvm_gcda_summary_info(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_summary_info);
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void llvm_gcda_end_file(void)
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{
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}
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EXPORT_SYMBOL(llvm_gcda_end_file);
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/**
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* gcov_info_filename - return info filename
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* @info: profiling data set
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*/
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const char *gcov_info_filename(struct gcov_info *info)
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{
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return info->filename;
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}
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/**
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* gcov_info_version - return info version
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* @info: profiling data set
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*/
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unsigned int gcov_info_version(struct gcov_info *info)
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{
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return info->version;
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}
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/**
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* gcov_info_next - return next profiling data set
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* @info: profiling data set
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*
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* Returns next gcov_info following @info or first gcov_info in the chain if
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* @info is %NULL.
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*/
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struct gcov_info *gcov_info_next(struct gcov_info *info)
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{
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if (!info)
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return list_first_entry_or_null(&clang_gcov_list,
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struct gcov_info, head);
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if (list_is_last(&info->head, &clang_gcov_list))
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return NULL;
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return list_next_entry(info, head);
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}
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/**
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* gcov_info_link - link/add profiling data set to the list
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* @info: profiling data set
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*/
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void gcov_info_link(struct gcov_info *info)
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{
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list_add_tail(&info->head, &clang_gcov_list);
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}
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/**
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* gcov_info_unlink - unlink/remove profiling data set from the list
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* @prev: previous profiling data set
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* @info: profiling data set
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*/
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void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
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{
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/* Generic code unlinks while iterating. */
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__list_del_entry(&info->head);
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}
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/**
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* gcov_info_within_module - check if a profiling data set belongs to a module
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* @info: profiling data set
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* @mod: module
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*
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* Returns true if profiling data belongs module, false otherwise.
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*/
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bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
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{
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return within_module((unsigned long)info->filename, mod);
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}
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/* Symbolic links to be created for each profiling data file. */
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const struct gcov_link gcov_link[] = {
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{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
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{ 0, NULL},
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};
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/**
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* gcov_info_reset - reset profiling data to zero
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* @info: profiling data set
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*/
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void gcov_info_reset(struct gcov_info *info)
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{
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struct gcov_fn_info *fn;
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list_for_each_entry(fn, &info->functions, head)
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memset(fn->counters, 0,
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sizeof(fn->counters[0]) * fn->num_counters);
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}
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/**
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* gcov_info_is_compatible - check if profiling data can be added
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* @info1: first profiling data set
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* @info2: second profiling data set
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*
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* Returns non-zero if profiling data can be added, zero otherwise.
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*/
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int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
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{
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struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
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&info1->functions, struct gcov_fn_info, head);
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struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
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&info2->functions, struct gcov_fn_info, head);
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if (info1->checksum != info2->checksum)
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return false;
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if (!fn_ptr1)
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return fn_ptr1 == fn_ptr2;
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while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
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!list_is_last(&fn_ptr2->head, &info2->functions)) {
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if (fn_ptr1->checksum != fn_ptr2->checksum)
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return false;
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if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
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return false;
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fn_ptr1 = list_next_entry(fn_ptr1, head);
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fn_ptr2 = list_next_entry(fn_ptr2, head);
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}
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return list_is_last(&fn_ptr1->head, &info1->functions) &&
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list_is_last(&fn_ptr2->head, &info2->functions);
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}
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/**
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* gcov_info_add - add up profiling data
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* @dest: profiling data set to which data is added
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* @source: profiling data set which is added
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*
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* Adds profiling counts of @source to @dest.
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*/
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void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
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{
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struct gcov_fn_info *dfn_ptr;
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struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
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struct gcov_fn_info, head);
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list_for_each_entry(dfn_ptr, &dst->functions, head) {
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u32 i;
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for (i = 0; i < sfn_ptr->num_counters; i++)
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dfn_ptr->counters[i] += sfn_ptr->counters[i];
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sfn_ptr = list_next_entry(sfn_ptr, head);
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}
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}
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static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
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{
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size_t cv_size; /* counter values size */
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struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
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GFP_KERNEL);
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if (!fn_dup)
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return NULL;
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INIT_LIST_HEAD(&fn_dup->head);
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cv_size = fn->num_counters * sizeof(fn->counters[0]);
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fn_dup->counters = kvmalloc(cv_size, GFP_KERNEL);
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if (!fn_dup->counters) {
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kfree(fn_dup);
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return NULL;
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}
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memcpy(fn_dup->counters, fn->counters, cv_size);
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return fn_dup;
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}
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/**
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* gcov_info_dup - duplicate profiling data set
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* @info: profiling data set to duplicate
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*
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* Return newly allocated duplicate on success, %NULL on error.
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*/
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struct gcov_info *gcov_info_dup(struct gcov_info *info)
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{
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struct gcov_info *dup;
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struct gcov_fn_info *fn;
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dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
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if (!dup)
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return NULL;
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INIT_LIST_HEAD(&dup->head);
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INIT_LIST_HEAD(&dup->functions);
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dup->filename = kstrdup(info->filename, GFP_KERNEL);
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if (!dup->filename)
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goto err;
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list_for_each_entry(fn, &info->functions, head) {
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struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);
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if (!fn_dup)
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goto err;
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list_add_tail(&fn_dup->head, &dup->functions);
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}
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return dup;
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err:
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gcov_info_free(dup);
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return NULL;
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}
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/**
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* gcov_info_free - release memory for profiling data set duplicate
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* @info: profiling data set duplicate to free
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*/
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void gcov_info_free(struct gcov_info *info)
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{
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struct gcov_fn_info *fn, *tmp;
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list_for_each_entry_safe(fn, tmp, &info->functions, head) {
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kvfree(fn->counters);
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list_del(&fn->head);
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kfree(fn);
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}
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kfree(info->filename);
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kfree(info);
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}
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/**
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* convert_to_gcda - convert profiling data set to gcda file format
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* @buffer: the buffer to store file data or %NULL if no data should be stored
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* @info: profiling data set to be converted
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*
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* Returns the number of bytes that were/would have been stored into the buffer.
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*/
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size_t convert_to_gcda(char *buffer, struct gcov_info *info)
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{
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struct gcov_fn_info *fi_ptr;
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size_t pos = 0;
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/* File header. */
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pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
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pos += store_gcov_u32(buffer, pos, info->version);
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pos += store_gcov_u32(buffer, pos, info->checksum);
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list_for_each_entry(fi_ptr, &info->functions, head) {
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u32 i;
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pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
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pos += store_gcov_u32(buffer, pos, 3);
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pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
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pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
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pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
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pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
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pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
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for (i = 0; i < fi_ptr->num_counters; i++)
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pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]);
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}
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return pos;
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}
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