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| author | Maciej Żenczykowski <maze@google.com> | 2021-11-18 12:23:02 -0800 |
|---|---|---|
| committer | Maciej Żenczykowski <maze@google.com> | 2021-11-19 01:18:12 +0000 |
| commit | e49e0c60cd52a3ff80b57f7aa4faf79d9d6a911e (patch) | |
| tree | 0bd3156e404771ac9fd3c91ecc04f64d97f03d41 /bpfloader | |
| parent | 210d6be5ac0dd8e76c683cb0f5d194ce3a19d224 (diff) | |
| download | bpf-e49e0c60cd52a3ff80b57f7aa4faf79d9d6a911e.tar.gz | |
document how to debug bpfloader failures
Test: N/A
Bug: 204131517
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ia6a8ca026f3ab403443e130dceb2aca0ce0f2343
Diffstat (limited to 'bpfloader')
| -rw-r--r-- | bpfloader/bpfloader.rc | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/bpfloader/bpfloader.rc b/bpfloader/bpfloader.rc index 53219f4..0d92cd8 100644 --- a/bpfloader/bpfloader.rc +++ b/bpfloader/bpfloader.rc @@ -57,6 +57,30 @@ service bpfloader /system/bin/bpfloader # rlimit memlock 1073741824 1073741824 oneshot + # + # How to debug bootloops caused by 'bpfloader-failed'. + # + # 1. On some lower RAM devices (like wembley) you may need to first enable developer mode + # (from the Settings app UI), and change the developer option "Logger buffer sizes" + # from the default (wembley: 64kB) to the maximum (1M) per log buffer. + # Otherwise buffer will overflow before you manage to dump it and you'll get useless logs. + # + # 2. comment out 'reboot_on_failure reboot,bpfloader-failed' below + # 3. rebuild/reflash/reboot + # 4. as the device is booting up capture bpfloader logs via: + # adb logcat -s 'bpfloader:*' 'LibBpfLoader:*' + # + # something like: + # $ adb reboot; sleep 1; adb wait-for-device; adb root; sleep 1; adb wait-for-device; adb logcat -s 'bpfloader:*' 'LibBpfLoader:*' + # will take care of capturing logs as early as possible + # + # 5. look through the logs from the kernel's bpf verifier that bpfloader dumps out, + # it usually makes sense to search back from the end and find the particular + # bpf verifier failure that caused bpfloader to terminate early with an error code. + # This will probably be something along the lines of 'too many jumps' or + # 'cannot prove return value is 0 or 1' or 'unsupported / unknown operation / helper', + # 'invalid bpf_context access', etc. + # reboot_on_failure reboot,bpfloader-failed # we're not really updatable, but want to be able to load bpf programs shipped in apexes updatable |