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From: Mike Rapoport <rppt@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: "Michael Neuling" <mikey@neuling.org>,
	"Björn Töpel" <bjorn@rivosinc.com>,
	"Vishal Moola (Oracle)" <vishal.moola@gmail.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Aleksa Paunovic" <aleksa.paunovic@htecgroup.com>,
	"Aleksandar Rikalo" <arikalo@gmail.com>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Andrew Jones" <ajones@ventanamicro.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Djordje Todorovic" <djordje.todorovic@htecgroup.com>,
	"Guo Ren" <guoren@kernel.org>,
	"Junhui Liu" <junhui.liu@pigmoral.tech>,
	"Kevin Brodsky" <kevin.brodsky@arm.com>,
	"Lorenzo Stoakes" <ljs@kernel.org>,
	"Nam Cao" <namcao@linutronix.de>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Oscar Salvador" <osalvador@suse.de>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Paul Walmsley" <pjw@kernel.org>,
	"Qinglin Pan" <panqinglin2020@iscas.ac.cn>,
	"Raj Vishwanathan4" <rvishwanathan@mips.com>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH 3/5] riscv: mm: Fix NULL pointer dereference in __set_memory
Date: Fri, 10 Apr 2026 10:53:57 +0300	[thread overview]
Message-ID: <adislUQ_dddOZZlW@kernel.org> (raw)
In-Reply-To: <c390be36-ac4a-4964-9072-7ccf074d2f7f@kernel.org>

On Fri, Apr 10, 2026 at 09:42:26AM +0200, David Hildenbrand (Arm) wrote:
> On 4/10/26 08:23, Michael Neuling wrote:
> >>>               area = find_vm_area((void *)start);
> >>> +             if (!area) {
> >>> +                     ret = -EINVAL;
> >>> +                     goto unlock;
> >>> +             }
> >>>               page_start = (start - (unsigned long)area->addr) >> PAGE_SHIFT;
> >>>
> >>>               for (i = page_start; i < page_start + numpages; ++i) {
> >>
> >> Which caller would end up calling __set_memory() in such a way?
> > 
> > It wouldn't. You're right on this and the other two. Sorry for the noise.
> 
> Slopped-by: Cursor:claude-4.6-opus-high-thinking
> 
> :)

It's a general tendency of LLMs to generate overly defensive code and raise
concerns about theoretical issues.
Maybe it's worth taking into account when writing prompts specific to
kernel development.
 
> Patch #1 seems reasonable (although non-critical); not sure about patch
> #2, leaving both to Risc-V people!
> 
> -- 
> Cheers,
> 
> David

-- 
Sincerely yours,
Mike.

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: "Michael Neuling" <mikey@neuling.org>,
	"Björn Töpel" <bjorn@rivosinc.com>,
	"Vishal Moola (Oracle)" <vishal.moola@gmail.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Aleksa Paunovic" <aleksa.paunovic@htecgroup.com>,
	"Aleksandar Rikalo" <arikalo@gmail.com>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Andrew Jones" <ajones@ventanamicro.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Djordje Todorovic" <djordje.todorovic@htecgroup.com>,
	"Guo Ren" <guoren@kernel.org>,
	"Junhui Liu" <junhui.liu@pigmoral.tech>,
	"Kevin Brodsky" <kevin.brodsky@arm.com>,
	"Lorenzo Stoakes" <ljs@kernel.org>,
	"Nam Cao" <namcao@linutronix.de>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Oscar Salvador" <osalvador@suse.de>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Paul Walmsley" <pjw@kernel.org>,
	"Qinglin Pan" <panqinglin2020@iscas.ac.cn>,
	"Raj Vishwanathan4" <rvishwanathan@mips.com>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH 3/5] riscv: mm: Fix NULL pointer dereference in __set_memory
Date: Fri, 10 Apr 2026 10:53:57 +0300	[thread overview]
Message-ID: <adislUQ_dddOZZlW@kernel.org> (raw)
In-Reply-To: <c390be36-ac4a-4964-9072-7ccf074d2f7f@kernel.org>

On Fri, Apr 10, 2026 at 09:42:26AM +0200, David Hildenbrand (Arm) wrote:
> On 4/10/26 08:23, Michael Neuling wrote:
> >>>               area = find_vm_area((void *)start);
> >>> +             if (!area) {
> >>> +                     ret = -EINVAL;
> >>> +                     goto unlock;
> >>> +             }
> >>>               page_start = (start - (unsigned long)area->addr) >> PAGE_SHIFT;
> >>>
> >>>               for (i = page_start; i < page_start + numpages; ++i) {
> >>
> >> Which caller would end up calling __set_memory() in such a way?
> > 
> > It wouldn't. You're right on this and the other two. Sorry for the noise.
> 
> Slopped-by: Cursor:claude-4.6-opus-high-thinking
> 
> :)

It's a general tendency of LLMs to generate overly defensive code and raise
concerns about theoretical issues.
Maybe it's worth taking into account when writing prompts specific to
kernel development.
 
> Patch #1 seems reasonable (although non-critical); not sure about patch
> #2, leaving both to Risc-V people!
> 
> -- 
> Cheers,
> 
> David

-- 
Sincerely yours,
Mike.

  reply	other threads:[~2026-04-10  7:54 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-09  9:11 [PATCH 0/5] riscv: Assorted bug fixes Michael Neuling
2026-04-09  9:11 ` Michael Neuling
2026-04-09  9:11 ` [PATCH 1/5] riscv: errata: Fix bitwise vs logical AND in MIPS errata patching Michael Neuling
2026-04-09  9:11   ` Michael Neuling
2026-05-01  2:08   ` Paul Walmsley
2026-05-01  2:08     ` Paul Walmsley
2026-04-09  9:11 ` [PATCH 2/5] riscv: ptrace: Fix register corruption in compat_riscv_gpr_set on error Michael Neuling
2026-04-09  9:11   ` Michael Neuling
2026-05-01  2:05   ` Paul Walmsley
2026-05-01  2:05     ` Paul Walmsley
2026-05-01  6:21     ` Michael Neuling
2026-05-01  6:21       ` Michael Neuling
2026-05-01  6:23     ` [PATCH v2] riscv: Fix register corruption from uninitialized cregs " Michael Neuling
2026-05-01  6:23       ` Michael Neuling
2026-05-02  3:14       ` Paul Walmsley
2026-05-02  3:14         ` Paul Walmsley
2026-04-09  9:11 ` [PATCH 3/5] riscv: mm: Fix NULL pointer dereference in __set_memory Michael Neuling
2026-04-09  9:11   ` Michael Neuling
2026-04-09 12:37   ` David Hildenbrand (Arm)
2026-04-09 12:37     ` David Hildenbrand (Arm)
2026-04-10  6:23     ` Michael Neuling
2026-04-10  6:23       ` Michael Neuling
2026-04-10  7:42       ` David Hildenbrand (Arm)
2026-04-10  7:42         ` David Hildenbrand (Arm)
2026-04-10  7:53         ` Mike Rapoport [this message]
2026-04-10  7:53           ` Mike Rapoport
2026-04-10  7:59           ` David Hildenbrand (Arm)
2026-04-10  7:59             ` David Hildenbrand (Arm)
2026-04-10  8:55             ` Michael Neuling
2026-04-10  8:55               ` Michael Neuling
2026-04-09  9:11 ` [PATCH 4/5] riscv: mm: Fix NULL dereferences in napot hugetlb functions Michael Neuling
2026-04-09  9:11   ` Michael Neuling
2026-04-09 12:36   ` David Hildenbrand (Arm)
2026-04-09 12:36     ` David Hildenbrand (Arm)
2026-04-09  9:11 ` [PATCH 5/5] riscv: mm: Fix TOCTOU race in remove_pte_mapping Michael Neuling
2026-04-09  9:11   ` Michael Neuling
2026-04-09 12:32   ` David Hildenbrand (Arm)
2026-04-09 12:32     ` David Hildenbrand (Arm)

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