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From: Dan Carpenter <dan.carpenter@oracle.com>
To: bp@suse.de
Cc: linux-edac@vger.kernel.org
Subject: [bug report] x86/mce: Prevent severity computation from being instrumented
Date: Fri, 17 Dec 2021 13:20:29 +0300	[thread overview]
Message-ID: <20211217102029.GA29708@kili> (raw)

Hello Borislav Petkov,

This is a semi-automatic email about new static checker warnings.

The patch 0a5b288e85bb: "x86/mce: Prevent severity computation from
being instrumented" from Oct 13, 2021, leads to the following Smatch
complaint:

    arch/x86/kernel/cpu/mce/severity.c:286 error_context()
    warn: variable dereferenced before check 'regs' (see line 280)

arch/x86/kernel/cpu/mce/severity.c
   279		fixup_type = ex_get_fixup_type(m->ip);
   280		copy_user  = is_copy_from_user(regs);
                                               ^^^^
New unchecked dereference

   281		instrumentation_end();
   282	
   283		switch (fixup_type) {
   284		case EX_TYPE_UACCESS:
   285		case EX_TYPE_COPY:
   286			if (!regs || !copy_user)
                             ^^^^
Old code checked for NULL

   287				return IN_KERNEL;
   288			m->kflags |= MCE_IN_KERNEL_COPYIN;

regards,
dan carpenter

             reply	other threads:[~2021-12-17 10:20 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-17 10:20 Dan Carpenter [this message]
2021-12-17 11:29 ` [bug report] x86/mce: Prevent severity computation from being instrumented Borislav Petkov
2021-12-17 17:13   ` Luck, Tony
2021-12-17 23:50     ` [PATCH] x86/mce: Check regs before accessing it Borislav Petkov

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