From: Al Viro viro@zeniv.linux.org.uk
stable inclusion from stable-v5.10.146 commit 12fda27a412b62cf136dd2600bff11bc814ee86a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 762df359aa5849e010ef04c3ed79d57588ce17d9 upstream.
riscv has an equivalent of arm bug fixed by 653d48b22166 ("arm: fix really nasty sigreturn bug"); if signal gets caught by an interrupt that hits when we have the right value in a0 (-513), *and* another signal gets delivered upon sigreturn() (e.g. included into the blocked mask for the first signal and posted while the handler had been running), the syscall restart logics will see regs->cause equal to EXC_SYSCALL (we are in a syscall, after all) and a0 already restored to its original value (-513, which happens to be -ERESTARTNOINTR) and assume that we need to apply the usual syscall restart logics.
Signed-off-by: Al Viro viro@zeniv.linux.org.uk Fixes: e2c0cdfba7f6 ("RISC-V: User-facing API") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/YxJEiSq%2FCGaL6Gm9@ZenIV/ Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Jialin Zhang zhangjialin11@huawei.com Reviewed-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/riscv/kernel/signal.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index bc6841867b51..529c123cf0a4 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -121,6 +121,8 @@ SYSCALL_DEFINE0(rt_sigreturn) if (restore_altstack(&frame->uc.uc_stack)) goto badframe;
+ regs->cause = -1UL; + return regs->a0;
badframe: