From: Al Viro <viro@zeniv.linux.org.uk> To: linux-riscv@lists.infradead.org Cc: Linus Torvalds <torvalds@linux-foundation.org>, linux-kernel@vger.kernel.org Subject: [PATCH] riscv: fix a nasty sigreturn bug... Date: Fri, 24 Sep 2021 01:55:27 +0000 [thread overview] Message-ID: <YU0wDzeS/jXwkAca@zeniv-ca.linux.org.uk> (raw) riscv has an equivalent of arm bug fixed by 653d48b22166; 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> --- diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index c2d5ecbe55264..f8fb85dc94b7a 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:
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk> To: linux-riscv@lists.infradead.org Cc: Linus Torvalds <torvalds@linux-foundation.org>, linux-kernel@vger.kernel.org Subject: [PATCH] riscv: fix a nasty sigreturn bug... Date: Fri, 24 Sep 2021 01:55:27 +0000 [thread overview] Message-ID: <YU0wDzeS/jXwkAca@zeniv-ca.linux.org.uk> (raw) riscv has an equivalent of arm bug fixed by 653d48b22166; 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> --- diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index c2d5ecbe55264..f8fb85dc94b7a 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: _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2021-09-24 1:55 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-24 1:55 Al Viro [this message] 2021-09-24 1:55 ` [PATCH] riscv: fix a nasty sigreturn bug Al Viro 2022-09-02 0:13 ` Al Viro 2022-09-02 0:13 ` Al Viro 2022-09-02 9:22 ` Andrew Jones 2022-09-02 9:22 ` Andrew Jones 2022-09-02 17:59 ` Al Viro 2022-09-02 17:59 ` Al Viro 2022-09-15 18:48 ` Palmer Dabbelt 2022-09-15 18:48 ` Palmer Dabbelt
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