On Tue, Mar 23, 2021 at 07:04:34PM -0700, Stephen Boyd wrote: > Add the running kernel's build ID[1] to the stacktrace information > header. This makes it simpler for developers to locate the vmlinux with > full debuginfo for a particular kernel stacktrace. Combined with > scripts/decode_stracktrace.sh, a developer can download the correct > vmlinux from a debuginfod[2] server and find the exact file and line > number for the functions plus offsets in a stacktrace. > > This is especially useful for pstore crash debugging where the kernel > crashes are recorded in the pstore logs and the recovery kernel is > different or the debuginfo doesn't exist on the device due to space > concerns (the data can be large and a security concern). The stacktrace > can be analyzed after the crash by using the build ID to find the > matching vmlinux and understand where in the function something went > wrong. > > Example stacktrace from lkdtm:
Can we drop the noise from the example and leave only important part(s)? > WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 > lkdtm_WARNING+0x28/0x30 [lkdtm] > Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup > uinput xt_MASQUERADE > CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 > aa23f7a1231c229de205662d5a9e0d4c580f19a1 > Hardware name: Google Lazor (rev3+) with KB Backlight (DT) > pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--) > pc : lkdtm_WARNING+0x28/0x30 [lkdtm] > lr : lkdtm_do_action+0x24/0x40 [lkdtm] > sp : ffffffc0134fbca0 > x29: ffffffc0134fbca0 x28: ffffff92d53ba240 > x27: 0000000000000000 x26: 0000000000000000 > x25: 0000000000000000 x24: ffffffe3622352c0 > x23: 0000000000000020 x22: ffffffe362233366 > x21: ffffffe3622352e0 x20: ffffffc0134fbde0 > x19: 0000000000000008 x18: 0000000000000000 > x17: ffffff929b6536fc x16: 0000000000000000 > x15: 0000000000000000 x14: 0000000000000012 > x13: ffffffe380ed892c x12: ffffffe381d05068 > x11: 0000000000000000 x10: 0000000000000000 > x9 : 0000000000000001 x8 : ffffffe362237000 > x7 : aaaaaaaaaaaaaaaa x6 : 0000000000000000 > x5 : 0000000000000000 x4 : 0000000000000001 > x3 : 0000000000000008 x2 : ffffff93fef25a70 > x1 : ffffff93fef15788 x0 : ffffffe3622352e0 > Call trace: > lkdtm_WARNING+0x28/0x30 [lkdtm] > direct_entry+0x16c/0x1b4 [lkdtm] > full_proxy_write+0x74/0xa4 > vfs_write+0xec/0x2e8 > ksys_write+0x84/0xf0 > __arm64_sys_write+0x24/0x30 > el0_svc_common+0xf4/0x1c0 > do_el0_svc_compat+0x28/0x3c > el0_svc_compat+0x10/0x1c > el0_sync_compat_handler+0xa8/0xcc > el0_sync_compat+0x178/0x180 > ---[ end trace 3d95032303e59e68 ]--- > > The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID, > following the kernel version number. -- With Best Regards, Andy Shevchenko
