On 03/14/24 at 12:54pm, Jiri Slaby wrote: > On 14. 03. 24, 11:39, Baoquan He wrote: > > Jiri reported that the current kexec_dprintk() always prints out > > debugging message whenever kexec/kdmmp loading is triggered. That is > > not wanted. The debugging message is supposed to be printed out when > > 'kexec -s -d' is specified for kexec/kdump loading. > > > > After investigating, the reason is the current kexec_dprintk() takes > > printk(KERN_INFO) or printk(KERN_DEBUG) depending on whether '-d' is > > specified. However, distros usually have defaulg log level like below: > > > > [~]# cat /proc/sys/kernel/printk > > 7 4 1 7 > > > > So, even though '-d' is not specified, printk(KERN_DEBUG) also always > > prints out. I thought printk(KERN_DEBUG) is equal to pr_debug(), it's > > not. > > > > Fix it by changing to use pr_info() and pr_debug() instead which are > > expected to work. > > Hi, > > sow, you'd need both -d, and dyndbg updates. Hence, again my question: > === > Actually what was wrong on the pr_debug()s? Can you simply turn them on from > the kernel when -d is passed to kexec instead of all this? I checked code, it's because some codes are shared by both kexec_load and kexec_file_load, e.g below function on arm64: arch/arm64/kernel/machine_kexec.c:machine_kexec_post_load() "kexec -c -l -d" is for kexec_load debugging message printing, it's all done in user space kexec-tools utility. The pr_debug() have been there for arm64 developer's debugging if they want to. I don't want to change that. If 'kexec -s -l -d', pr_info() is called to print out. If 'kexec -s -l' w/o '-d', or 'kexec -c -l', it's still pr_debug just as before. > === > > And yet, it is still missing a prefix :). It looks like this now, seems no need to add prefix. [ 102.609784] kexec_file: kernel: 0000000081fc03e0 kernel_size: 0xccb200 [ 102.617084] PEFILE: Unsigned PE binary [ 102.753174] ima: kexec measurement buffer for the loaded kernel at 0x71435000. [ 102.761335] kexec-bzImage64: Loaded purgatory at 0x71430000 [ 102.767571] kexec-bzImage64: Loaded boot_param, command line and misc at 0x7142c000 bufsz=0x1320 memsz=0x2000 [ 102.778650] kexec-bzImage64: Loaded 64bit kernel at 0x6d000000 bufsz=0xcc6200 memsz=0x3c4c000 [ 102.788251] kexec-bzImage64: Loaded initrd at 0x6ac0f000 bufsz=0x23f0175 memsz=0x23f0175 [ 102.797283] kexec-bzImage64: Final command line is: root=/dev/mapper/fedora_lenovo--electron--sr850--01-root ro rd.lvm.lv=fedora_lenovo-electron-sr850-01/root console=ttyS0,115200n81 [ 102.815435] kexec-bzImage64: E820 memmap: [ 102.819912] kexec-bzImage64: 0000000000000000-000000000003dfff (1) [ 102.826817] kexec-bzImage64: 000000000003e000-000000000003ffff (2) [ 103.021435] kexec-bzImage64: 00000000ff000000-00000000ffffffff (2) ......snip [ 103.028336] kexec-bzImage64: 0000000100000000-000000403fffffff (1) [ 103.269194] kexec_file: nr_segments = 5 [ 103.273484] kexec_file: segment[0]: buf=0x00000000898981dd bufsz=0x59e mem=0x71435000 memsz=0x1000 [ 103.283616] kexec_file: segment[1]: buf=0x000000003d8dd363 bufsz=0x4000 mem=0x71430000 memsz=0x5000 [ 103.293748] kexec_file: segment[2]: buf=0x00000000ba27c5ef bufsz=0x1320 mem=0x7142c000 memsz=0x2000 [ 103.303865] kexec_file: segment[3]: buf=0x0000000026acdcf4 bufsz=0xcc6200 mem=0x6d000000 memsz=0x3c4c000 [ 103.333455] kexec_file: segment[4]: buf=0x000000001a7dac7f bufsz=0x23f0175 mem=0x6ac0f000 memsz=0x23f1000 [ 103.356698] kexec_file: kexec_file_load: type:0, start:0x714301a0 head:0x1222da002 flags:0x8 _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
