From: Xianting Tian <xianting.tian@linux.alibaba.com>
To: Dan Carpenter <dan.carpenter@oracle.com>, kbuild@lists.01.org
Cc: lkp@intel.com, kbuild-all@lists.01.org,
linux-kernel@vger.kernel.org,
Palmer Dabbelt <palmer@rivosinc.com>, Guo Ren <guoren@kernel.org>
Subject: Re: arch/riscv/kernel/traps.c:48 die() warn: variable dereferenced before check 'regs' (see line 46)
Date: Thu, 11 Aug 2022 18:42:28 +0800 [thread overview]
Message-ID: <f6780b5a-5ce2-a7f3-dffa-2a5e5e0b2bd1@linux.alibaba.com> (raw)
In-Reply-To: <202208110538.uaLOQmBs-lkp@intel.com>
在 2022/8/11 下午6:33, Dan Carpenter 写道:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: f41445645ab5d172e6090d00c332c335d8dba337
> commit: 3f1901110a89b0e2e13adb2ac8d1a7102879ea98 RISC-V: Add fast call path of crash_kexec()
> config: riscv-randconfig-m031-20220810 (https://download.01.org/0day-ci/archive/20220811/202208110538.uaLOQmBs-lkp@intel.com/config)
> compiler: riscv64-linux-gcc (GCC) 12.1.0
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> smatch warnings:
> arch/riscv/kernel/traps.c:48 die() warn: variable dereferenced before check 'regs' (see line 46)
>
> vim +/regs +48 arch/riscv/kernel/traps.c
>
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 31 void die(struct pt_regs *regs, const char *str)
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 32 {
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 33 static int die_counter;
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 34 int ret;
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 35
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 36 oops_enter();
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 37
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 38 spin_lock_irq(&die_lock);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 39 console_verbose();
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 40 bust_spinlocks(1);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 41
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 42 pr_emerg("%s [#%d]\n", str, ++die_counter);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 43 print_modules();
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 44 show_regs(regs);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 45
> a4c3733d32a72f Christoph Hellwig 2019-10-28 @46 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
> ^^^^^^^^^^^
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 47
> 3f1901110a89b0 Xianting Tian 2022-06-06 @48 if (regs && kexec_should_crash(current))
> ^^^^
>
> Delete this NULL check.
thanks, I will send another fixup patch to fix the issue, is it OK?
>
> 3f1901110a89b0 Xianting Tian 2022-06-06 49 crash_kexec(regs);
> 3f1901110a89b0 Xianting Tian 2022-06-06 50
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 51 bust_spinlocks(0);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 52 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 53 spin_unlock_irq(&die_lock);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 54 oops_exit();
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 55
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 56 if (in_interrupt())
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 57 panic("Fatal exception in interrupt");
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 58 if (panic_on_oops)
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 59 panic("Fatal exception");
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 60 if (ret != NOTIFY_STOP)
> 0e25498f8cd43c Eric W. Biederman 2021-06-28 61 make_task_dead(SIGSEGV);
> 76d2a0493a17d4 Palmer Dabbelt 2017-07-10 62 }
>
next prev parent reply other threads:[~2022-08-11 10:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-11 10:33 Dan Carpenter
2022-08-11 10:42 ` Xianting Tian [this message]
2022-09-20 20:06 ` Palmer Dabbelt
2022-09-21 1:35 ` Xianting Tian
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