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charset=us-ascii Content-Disposition: inline In-Reply-To: <1ff716d3-eb3d-477e-ae30-1abe97eee01b@linux.alibaba.com> X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CFD0C10001B X-Stat-Signature: xa6bnmaj7kqchxzbyf5jccnooutc1iye X-HE-Tag: 1739888148-12772 X-HE-Meta: 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 fXrnAEyF hokXoZJQM+5hu1ry8xshhiLa2tjGDD6cm/matb9E9IEbP/90bHJWt736tu+Cm4WXulcU4Oo4qXwCUhk4CXCvlQhh8wqKabsotASHx72d7g1RC3rceTushkzd3lXJYaLz86lor1Z4Y2yH0VMIvslXSBLwMeSJF/e20DODKmIPUXeO15ncUj98BaowFOXUhciJPh/qCd3P+YaT+qMrSE45IXyo4N7l51DENLhLSsEykC55alIJEO/r6BRejey9c1OEBFSPRXKdpgdQ4Xyox+6KAy1N2E90jsXdOljhXMxudRuY1l5yz603DDVFCPQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Feb 18, 2025 at 09:28:33PM +0800, Shuai Xue wrote: > I did build and test this patch set on it. But I did not find any warnings. > Could you provide more details? NOINSTR_VALIDATION=y helps > > > /* Allow instrumentation around external facilities usage. */ > > > instrumentation_begin(); > > > - fixup_type = ex_get_fixup_type(m->ip); > > > + fixup_type = FIELD_GET(EX_DATA_TYPE_MASK, e->data); > > > + imm = FIELD_GET(EX_DATA_IMM_MASK, e->data); > > > copy_user = is_copy_from_user(regs); > > > instrumentation_end(); > > > @@ -304,9 +311,13 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs) > > > case EX_TYPE_UACCESS: > > > if (!copy_user) > > > return IN_KERNEL; > > > - m->kflags |= MCE_IN_KERNEL_COPYIN; > > > - fallthrough; > > > - > > > + m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_RECOV; > > > + return IN_KERNEL_RECOV; > > > + case EX_TYPE_IMM_REG: > > > + if (!copy_user || imm != -EFAULT) > > > + return IN_KERNEL; > > > + m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_RECOV; > > > + return IN_KERNEL_RECOV; > > > > Maybe I'm justnot understanding things, but what's wrong with something > > like the below; why do we care about the ex-type if we know its a MOV > > reading from userspace? > > > > The less we muck about with the extable here, the better. > > We need to make sure that we have register a fixup handler for the copy_user > case. If no fixup handler found, the PC accessing posion will trigger #MCE > again and again resulting a hardlock up. Well, then write it like so. Afaict, you don't care what the actual exception type is, just that there is one, for the copy_user case. diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c index dac4d64dfb2a..cfdae25eacd7 100644 --- a/arch/x86/kernel/cpu/mce/severity.c +++ b/arch/x86/kernel/cpu/mce/severity.c @@ -301,18 +301,19 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs) instrumentation_end(); switch (fixup_type) { - case EX_TYPE_UACCESS: - if (!copy_user) - return IN_KERNEL; - m->kflags |= MCE_IN_KERNEL_COPYIN; - fallthrough; - case EX_TYPE_FAULT_MCE_SAFE: case EX_TYPE_DEFAULT_MCE_SAFE: m->kflags |= MCE_IN_KERNEL_RECOV; return IN_KERNEL_RECOV; default: + if (copy_user) { + m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_RECOV; + return IN_KERNEL_RECOV; + } + fallthrough; + + case EX_TYPE_NONE: return IN_KERNEL; } }