public-mirrors/linux
1
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-18 22:14:16 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

riscv: ftrace: Properly acquire text_mutex to fix a race condition

Browse source 
As reported by lockdep, some patching was done without acquiring
text_mutex, so there could be a race when mapping the page to patch
since we use the same fixmap entry.

Reported-by: Han Gao <rabenda.cn@gmail.com>
Reported-by: Vivian Wang <wangruikang@iscas.ac.cn>
Reported-by: Yao Zi <ziyao@disroot.org>
Closes: https://lore.kernel.org/linux-riscv/aGODMpq7TGINddzM@pie.lan/
Tested-by: Yao Zi <ziyao@disroot.org>
Tested-by: Han Gao <rabenda.cn@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250711-alex-fixes-v2-1-d85a5438da6c@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Alexandre Ghiti 2025-07-11 07:38:38 +00:00 • committed by Palmer Dabbelt
parent 16d743606d
commit e3f16d63d5
No known key found for this signature in database
GPG key ID: 2E1319F35FBB1889
1 changed files with 14 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
arch/riscv/kernel/ftrace.c
View file

@ -14,6 +14,18 @@
#include <asm/text-patching.h>
#ifdef CONFIG_DYNAMIC_FTRACE
void ftrace_arch_code_modify_prepare(void)
__acquires(&text_mutex)
{
mutex_lock(&text_mutex);
}
void ftrace_arch_code_modify_post_process(void)
__releases(&text_mutex)
{
mutex_unlock(&text_mutex);
}
unsigned long ftrace_call_adjust(unsigned long addr)
{
if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
@ -29,10 +41,8 @@ unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip)
void arch_ftrace_update_code(int command)
{
mutex_lock(&text_mutex);
command |= FTRACE_MAY_SLEEP;
ftrace_modify_all_code(command);
mutex_unlock(&text_mutex);
flush_icache_all();
}
@ -149,6 +159,8 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
unsigned int nops[2], offset;
int ret;
guard(mutex)(&text_mutex);
ret = ftrace_rec_set_nop_ops(rec);
if (ret)
return ret;
@ -157,9 +169,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
nops[0] = to_auipc_t0(offset);
nops[1] = RISCV_INSN_NOP4;
mutex_lock(&text_mutex);
ret = patch_insn_write((void *)pc, nops, 2 * MCOUNT_INSN_SIZE);
mutex_unlock(&text_mutex);
return ret;
}