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AJvYcCW1c81pJeH0upZnz4IleuSO3R9MrCQoYg4a9k2VfVcRrk2pugL2/88w2p/fh05rvWcTfFdguNkr0yMAsGbv4iRuOhEq2ILCp1iiKKWH X-Gm-Message-State: AOJu0YyXZuTkDHQ7HFuOk+yB5fMxUaZ3+o4VFlW3a+8DV6V8x9eVTUWi ue2DVrU4d8CnXJa7U5Sh9hdYnXiHaPTfGiNQjZ5QX5p8wOgiVVyD6KC9M0VDB5c= X-Google-Smtp-Source: AGHT+IF6DZcN4m8qC/kqVtmMb4RhqugcHjLxIwZZ8uE+ZCC+rM98YEmL0kMFn4CSRlFeKKenBvE4TQ== X-Received: by 2002:a05:6602:27d2:b0:7fa:244c:bfe9 with SMTP id ca18e2360f4ac-81ab6a10342mr675109439f.1.1721667355857; Mon, 22 Jul 2024 09:55:55 -0700 (PDT) Received: from localhost ([140.82.166.162]) by smtp.gmail.com with ESMTPSA id ca18e2360f4ac-819aba10e3bsm253873339f.7.2024.07.22.09.55.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jul 2024 09:55:55 -0700 (PDT) Date: Mon, 22 Jul 2024 11:55:54 -0500 From: Andrew Jones To: Yunhui Cui Cc: punit.agrawal@bytedance.com, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, akpm@linux-foundation.org, surenb@google.com, peterx@redhat.com, alexghiti@rivosinc.com, willy@infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] riscv/mm/fault: add show_pte() before die() Message-ID: <20240722-a0d01590ba9ec0e0cc18ac74@orel> References: <20240722042037.27934-1-cuiyunhui@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240722042037.27934-1-cuiyunhui@bytedance.com> On Mon, Jul 22, 2024 at 12:20:37PM GMT, Yunhui Cui wrote: > When the kernel displays "Unable to handle kernel paging request at > virtual address", we would like to confirm the status of the virtual > address in the page table. So add show_pte() before die(). > > Signed-off-by: Yunhui Cui > Reviewed-by: Alexandre Ghiti > --- > arch/riscv/mm/fault.c | 53 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 53 insertions(+) > > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c > index 5224f3733802..666d282a8bf4 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -22,6 +22,58 @@ > > #include "../kernel/head.h" > > +static void show_pte(unsigned long addr) > +{ > + pgd_t *pgdp, pgd; > + p4d_t *p4dp, p4d; > + pud_t *pudp, pud; > + pmd_t *pmdp, pmd; > + pte_t *ptep, pte; > + struct mm_struct *mm = current->mm; > + > + if (!mm) > + mm = &init_mm; > + > + pr_alert("Current %s pgtable: %luK pagesize, %d-bit VAs, pgdp=0x%016lx\n", > + current->comm, PAGE_SIZE/SZ_1K, VA_BITS, > + (mm == &init_mm ? __pa_symbol(mm->pgd) : > + (unsigned long)virt_to_phys(mm->pgd))); nit: unnecessary () around the ternary. > + > + pgdp = pgd_offset(mm, addr); > + pgd = pgdp_get(pgdp); > + pr_alert("[%016lx] pgd=%016lx", addr, pgd_val(pgd)); > + if (pgd_none(pgd) || pgd_bad(pgd) || pgd_leaf(pgd)) > + goto out; > + > + p4dp = p4d_offset(pgdp, addr); > + p4d = p4dp_get(p4dp); > + pr_cont(", p4d=%016lx", p4d_val(p4d)); > + if (p4d_none(p4d) || p4d_bad(p4d) || p4d_leaf(p4d)) > + goto out; > + > + pudp = pud_offset(p4dp, addr); > + pud = pudp_get(pudp); > + pr_cont(", pud=%016lx", pud_val(pud)); > + if (pud_none(pud) || pud_bad(pud) || pud_leaf(pud)) > + goto out; > + > + pmdp = pmd_offset(pudp, addr); > + pmd = pmdp_get(pmdp); > + pr_cont(", pmd=%016lx", pmd_val(pmd)); > + if (pmd_none(pmd) || pmd_bad(pmd) || pmd_leaf(pmd)) > + goto out; > + > + ptep = pte_offset_map(pmdp, addr); > + if (!ptep) > + goto out; > + > + pte = ptep_get(ptep); > + pr_cont(", pte=%016lx", pte_val(pte)); > + pte_unmap(ptep); > +out: > + pr_cont("\n"); > +} > + > static void die_kernel_fault(const char *msg, unsigned long addr, > struct pt_regs *regs) > { > @@ -31,6 +83,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr, > addr); > > bust_spinlocks(0); > + show_pte(addr); > die(regs, "Oops"); > make_task_dead(SIGKILL); > } > -- > 2.39.2 > > Reviewed-by: Andrew Jones Thanks, drew