linux-kernel - drivers/hv/hv_common.c:242 hv_kmsg_dump() error: uninitialized symbol 'bytes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <202512172102.OcUspn1Z-lkp@intel.com>
Date: Wed, 17 Dec 2025 16:23:38 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: oe-kbuild@...ts.linux.dev, Roman Kisel <romank@...ux.microsoft.com>
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev,
	linux-kernel@...r.kernel.org, Wei Liu <wei.liu@...nel.org>,
	Michael Kelley <mhklinux@...look.com>
Subject: drivers/hv/hv_common.c:242 hv_kmsg_dump() error: uninitialized
 symbol 'bytes_written'.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   ea1013c1539270e372fc99854bc6e4d94eaeff66
commit: f41ceff1748612b9e1538becc13dc2f1617d9d14 Drivers: hv: Enable VTL mode for arm64
date:   7 months ago
config: arm64-randconfig-r072-20251216 (https://download.01.org/0day-ci/archive/20251217/202512172102.OcUspn1Z-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 1335a05ab8bc8339ce24be3a9da89d8c3f4e0571)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
| Closes: https://lore.kernel.org/r/202512172102.OcUspn1Z-lkp@intel.com/

smatch warnings:
drivers/hv/hv_common.c:242 hv_kmsg_dump() error: uninitialized symbol 'bytes_written'.

vim +/bytes_written +242 drivers/hv/hv_common.c

9c318a1d9b5000 Long Li         2023-04-20  225  static void hv_kmsg_dump(struct kmsg_dumper *dumper,
e1a261ba599eec Jocelyn Falempe 2024-07-02  226  			 struct kmsg_dump_detail *detail)
9c318a1d9b5000 Long Li         2023-04-20  227  {
9c318a1d9b5000 Long Li         2023-04-20  228  	struct kmsg_dump_iter iter;
9c318a1d9b5000 Long Li         2023-04-20  229  	size_t bytes_written;
9c318a1d9b5000 Long Li         2023-04-20  230  
9c318a1d9b5000 Long Li         2023-04-20  231  	/* We are only interested in panics. */
e1a261ba599eec Jocelyn Falempe 2024-07-02  232  	if (detail->reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg)
9c318a1d9b5000 Long Li         2023-04-20  233  		return;
9c318a1d9b5000 Long Li         2023-04-20  234  
9c318a1d9b5000 Long Li         2023-04-20  235  	/*
9c318a1d9b5000 Long Li         2023-04-20  236  	 * Write dump contents to the page. No need to synchronize; panic should
9c318a1d9b5000 Long Li         2023-04-20  237  	 * be single-threaded.
9c318a1d9b5000 Long Li         2023-04-20  238  	 */
9c318a1d9b5000 Long Li         2023-04-20  239  	kmsg_dump_rewind(&iter);
9c318a1d9b5000 Long Li         2023-04-20  240  	kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
9c318a1d9b5000 Long Li         2023-04-20  241  			     &bytes_written);

kmsg_dump_get_buffer() is a no-op if CONFIG_PRINTK is disabled.

9c318a1d9b5000 Long Li         2023-04-20 @242  	if (!bytes_written)
                                                            ^^^^^^^^^^^^^^
uninitialized.

9c318a1d9b5000 Long Li         2023-04-20  243  		return;
9c318a1d9b5000 Long Li         2023-04-20  244  	/*
9c318a1d9b5000 Long Li         2023-04-20  245  	 * P3 to contain the physical address of the panic page & P4 to
9c318a1d9b5000 Long Li         2023-04-20  246  	 * contain the size of the panic data in that page. Rest of the
9c318a1d9b5000 Long Li         2023-04-20  247  	 * registers are no-op when the NOTIFY_MSG flag is set.
9c318a1d9b5000 Long Li         2023-04-20  248  	 */
0e3f7d120086c8 Nuno Das Neves  2024-02-20  249  	hv_set_msr(HV_MSR_CRASH_P0, 0);
0e3f7d120086c8 Nuno Das Neves  2024-02-20  250  	hv_set_msr(HV_MSR_CRASH_P1, 0);
0e3f7d120086c8 Nuno Das Neves  2024-02-20  251  	hv_set_msr(HV_MSR_CRASH_P2, 0);
0e3f7d120086c8 Nuno Das Neves  2024-02-20  252  	hv_set_msr(HV_MSR_CRASH_P3, virt_to_phys(hv_panic_page));
0e3f7d120086c8 Nuno Das Neves  2024-02-20  253  	hv_set_msr(HV_MSR_CRASH_P4, bytes_written);
9c318a1d9b5000 Long Li         2023-04-20  254  
9c318a1d9b5000 Long Li         2023-04-20  255  	/*
9c318a1d9b5000 Long Li         2023-04-20  256  	 * Let Hyper-V know there is crash data available along with
9c318a1d9b5000 Long Li         2023-04-20  257  	 * the panic message.
9c318a1d9b5000 Long Li         2023-04-20  258  	 */
0e3f7d120086c8 Nuno Das Neves  2024-02-20  259  	hv_set_msr(HV_MSR_CRASH_CTL,
9c318a1d9b5000 Long Li         2023-04-20  260  		   (HV_CRASH_CTL_CRASH_NOTIFY |
9c318a1d9b5000 Long Li         2023-04-20  261  		    HV_CRASH_CTL_CRASH_NOTIFY_MSG));
9c318a1d9b5000 Long Li         2023-04-20  262  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki