Hi bevis_chen, Thanks for the patch, only some small fixes: arm64_recalc_KERNELPACMASK is a void function, no need for the int ret = IKCONFIG_N; In fact, the ret variable is not necessary. Other than that, the patch is looking good for me. Thanks, Tao Liu On Wed, Jul 3, 2024 at 9:40 PM cb126yx <cb126yx@xxxxxxx> wrote: > > Hi all, > I may found a potential bug when using qcom arm64 ramdump to parse backtrace. > Unfortunately, I actually found no processes can use the bt command correctly. > > Ex: when start crash tool to do analyse: # crash vmlinux --kaslr=xxx DDRCS0_0.BIN@0x0000000080000000,... --machdep vabits_actual=39 > > Then seen below misleading backtrace information : > > crash> bt 16930 > > PID: 16930 TASK: ffffff89b3eada00 CPU: 2 COMMAND: "Firebase Backgr" > > #0 [ffffffc034c437f0] __switch_to at ffffffe0036832d4 > > #1 [ffffffc034c43850] __kvm_nvhe_$d.2314 at 6be732e004cf05a0 > > #2 [ffffffc034c438b0] __kvm_nvhe_$d.2314 at 86c54c6004ceff80 > > #3 [ffffffc034c43950] __kvm_nvhe_$d.2314 at 55d6f96003a7b120 > > #4 [ffffffc034c439f0] __kvm_nvhe_$d.2314 at 9ccec46003a80a64 > > #5 [ffffffc034c43ac0] __kvm_nvhe_$d.2314 at 8cf41e6003a945c4 > > #6 [ffffffc034c43b10] __kvm_nvhe_$d.2314 at a8f181e00372c818 > > #7 [ffffffc034c43b40] __kvm_nvhe_$d.2314 at 6dedde600372c0d0 > > #8 [ffffffc034c43b90] __kvm_nvhe_$d.2314 at 62cc07e00373d0ac > > #9 [ffffffc034c43c00] __kvm_nvhe_$d.2314 at 72fb1de00373bedc > > ... > > PC: 00000073f5294840 LR: 00000070d8f39ba4 SP: 00000070d4afd5d0 > > X29: 00000070d4afd600 X28: b4000071efcda7f0 X27: 00000070d4afe000 > > X26: 0000000000000000 X25: 00000070d9616000 X24: 0000000000000000 > > X23: 0000000000000000 X22: 0000000000000000 X21: 0000000000000000 > > X20: b40000728fd27520 X19: b40000728fd27550 X18: 000000702daba000 > > X17: 00000073f5294820 X16: 00000070d940f9d8 X15: 00000000000000bf > > X14: 0000000000000000 X13: 00000070d8ad2fac X12: b40000718fce5040 > > X11: 0000000000000000 X10: 0000000000000070 X9: 0000000000000001 > > X8: 0000000000000062 X7: 0000000000000020 X6: 0000000000000000 > > X5: 0000000000000000 X4: 0000000000000000 X3: 0000000000000000 > > X2: 0000000000000002 X1: 0000000000000080 X0: b40000728fd27550 > > ORIG_X0: b40000728fd27550 SYSCALLNO: ffffffff PSTATE: 40001000 > > > By checking the raw data below, will see the lr (fp+8) data show the pointer which already been replaced by PAC prefix. > > > crash> bt -f > > PID: 16930 TASK: ffffff89b3eada00 CPU: 2 COMMAND: "Firebase Backgr" > > #0 [ffffffc034c437f0] __switch_to at ffffffe0036832d4 > > ffffffc034c437f0: ffffffc034c43850 6be732e004cf05a4 > > ffffffc034c43800: ffffffe006186108 a0ed07e004cf09c4 > > ffffffc034c43810: ffffff8a1a340000 ffffff8a8d343c00 > > ffffffc034c43820: ffffff89b3eada00 ffffff8b780db540 > > ffffffc034c43830: ffffff89b3eada00 0000000000000000 > > ffffffc034c43840: 0000000000000004 712b828118484a00 > > #1 [ffffffc034c43850] __kvm_nvhe_$d.2314 at 6be732e004cf05a0 > > ffffffc034c43850: ffffffc034c438b0 86c54c6004ceff84 > > ffffffc034c43860: 000000708070f000 ffffffc034c43938 > > ffffffc034c43870: ffffff88bd822878 ffffff89b3eada00 > > ... > > > So we check the CONFIG_ARM64_PTR_AUTH and CONFIG_ARM64_PTR_AUTH_KERNEL to double check if pac mechanism been enabled on this ramdump. > > Then we use vabits to figure it out. > > Fix then show the right backtrace below: > > crash> bt 16930 > > PID: 16930 TASK: ffffff89b3eada00 CPU: 2 COMMAND: "Firebase Backgr" > > #0 [ffffffc034c437f0] __switch_to at ffffffe0036832d4 > > #1 [ffffffc034c43850] __schedule at ffffffe004cf05a0 > > #2 [ffffffc034c438b0] preempt_schedule_common at ffffffe004ceff80 > > #3 [ffffffc034c43950] unmap_page_range at ffffffe003a7b120 > > #4 [ffffffc034c439f0] unmap_vmas at ffffffe003a80a64 > > #5 [ffffffc034c43ac0] exit_mmap at ffffffe003a945c4 > > #6 [ffffffc034c43b10] __mmput at ffffffe00372c818 > > #7 [ffffffc034c43b40] mmput at ffffffe00372c0d0 > > #8 [ffffffc034c43b90] exit_mm at ffffffe00373d0ac > > #9 [ffffffc034c43c00] do_exit at ffffffe00373bedc > > PC: 00000073f5294840 LR: 00000070d8f39ba4 SP: 00000070d4afd5d0 > > X29: 00000070d4afd600 X28: b4000071efcda7f0 X27: 00000070d4afe000 > > X26: 0000000000000000 X25: 00000070d9616000 X24: 0000000000000000 > > X23: 0000000000000000 X22: 0000000000000000 X21: 0000000000000000 > > X20: b40000728fd27520 X19: b40000728fd27550 X18: 000000702daba000 > > X17: 00000073f5294820 X16: 00000070d940f9d8 X15: 00000000000000bf > > X14: 0000000000000000 X13: 00000070d8ad2fac X12: b40000718fce5040 > > X11: 0000000000000000 X10: 0000000000000070 X9: 0000000000000001 > > X8: 0000000000000062 X7: 0000000000000020 X6: 0000000000000000 > > X5: 0000000000000000 X4: 0000000000000000 X3: 0000000000000000 > > X2: 0000000000000002 X1: 0000000000000080 X0: b40000728fd27550 > > ORIG_X0: b40000728fd27550 SYSCALLNO: ffffffff PSTATE: 40001000 > > > Let's use GENMASK to replace the pac pointer to fix it. > > gki related commit url here: > > https://lore.kernel.org/all/20230412160134.306148-4-mark.rutland@xxxxxxx/ > > -- > Crash-utility mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx > To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxxxxxx > https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ 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