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@chengruizhe chengruizhe commented Jul 12, 2022

When there is not enough entropy in std::random_device, it can return identical results. If two uprobes with long and very similar names get deployed together, their names, when shortened, can be exactly the same. Combined with the lack of randomness, this can cause a uprobe deployment failure.

This diff fixes this issue by using the hash of the name instead.

Test plan:
Tested with dynamic_trace_bpf_test on Enigma where this issue shows up.

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Could you test this change with local_dev?
See https://phab.corp.pixielabs.ai/D11804 for a slight addition to the instructions.

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Tests have passed.

JamesMBartlett pushed a commit that referenced this pull request Dec 8, 2022
…for -v option

Add additional information and change format of backtrace
- add symbol base offset, dso name, dso base offset
- symbol and dso info is included if it's available in target binary
- changed format:
INDEX ADDR [SYMBOL+OFFSET] (MODULE+OFFSET)

Print backtrace of ip if it failed to get syms.

Before:
  # offcputime -v
    psiginfo
    vscanf
    __snprintf_chk
    [unknown]
    [unknown]
    [unknown]
    [unknown]
    [unknown]
    sd_event_exit
    sd_event_dispatch
    sd_event_run
    [unknown]
    __libc_start_main
    [unknown]
    -                systemd-journal (204)
        1

    xas_load
    xas_find
    filemap_map_pages
    __handle_mm_fault
    handle_mm_fault
    do_page_fault
    do_translation_fault
    do_mem_abort
    do_el0_ia_bp_hardening
    el0_ia
    xas_load
    --
failed to get syms
      -                PmLogCtl (138757)
        1

After:
  # offcputime -v
    #0  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
    #1  0xffffffc01009a93c el0_svc_handler+0x34
    #2  0xffffffc010084a08 el0_svc+0x8
    #3  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
    --
    #4  0x0000007fa0bffd14 clock_nanosleep+0x94 (/usr/lib/libc-2.31.so+0x9ed14)
    #5  0x0000007fa0c0530c nanosleep+0x1c (/usr/lib/libc-2.31.so+0xa430c)
    #6  0x0000007fa0c051e4 sleep+0x34 (/usr/lib/libc-2.31.so+0xa41e4)
    #7  0x000000558a5a9608 flb_loop+0x28 (/usr/bin/fluent-bit+0x52608)
    #8  0x000000558a59f1c4 flb_main+0xa84 (/usr/bin/fluent-bit+0x481c4)
    #9  0x0000007fa0b85124 __libc_start_main+0xe4 (/usr/lib/libc-2.31.so+0x24124)
    iovisor#10 0x000000558a59d828 _start+0x34 (/usr/bin/fluent-bit+0x46828)
    -                fluent-bit (1238)
        1

    #0  0xffffffc01027daa4 generic_copy_file_checks+0x334
    #1  0xffffffc0102ba634 __handle_mm_fault+0x8dc
    #2  0xffffffc0102baa20 handle_mm_fault+0x168
    #3  0xffffffc010ad23c0 do_page_fault+0x148
    #4  0xffffffc010ad27c0 do_translation_fault+0xb0
    #5  0xffffffc0100816b0 do_mem_abort+0x50
    #6  0xffffffc0100843b0 el0_da+0x1c
    #7  0xffffffc01027daa4 generic_copy_file_checks+0x334
    --
    #8  0x0000007f8dc12648 [unknown]
    #9  0x0000007f8dc0aef8 [unknown]
    iovisor#10 0x0000007f8dc1c990 [unknown]
    iovisor#11 0x0000007f8dc08b0c [unknown]
    iovisor#12 0x0000007f8dc08e48 [unknown]
    iovisor#13 0x0000007f8dc081c8 [unknown]
    -                PmLogCtl (2412)
        1

Fixed: iovisor#3884
Signed-off-by: Eunseon Lee <[email protected]>
@oazizi000
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Addressed in a different way by #7. Both implementations are pretty effective. #7 was preferred because it will allow us to attach multiple uprobes to the same symbol (even though we never currently do).

@oazizi000 oazizi000 closed this Dec 21, 2022
ddelnano pushed a commit that referenced this pull request Oct 9, 2024
…option

Add additional information and change format of backtrace
- add symbol base offset, dso name, dso base offset
- symbol and dso info is included if it's available in target binary
- changed format:
INDEX ADDR [SYMBOL+OFFSET] (MODULE+OFFSET)

before:
  # ./capable -UK
    TIME     UID   PID     COMM             CAP     NAME                 AUDIT   VER DICT
    01:59:17 0     730     irqbalance       21      CAP_SYS_ADMIN        0       deny
        cap_vm_enough_memory
        security_vm_enough_memory_mm
        mmap_region
        do_mmap
        vm_mmap_pgoff
        do_syscall_64
        entry_SYSCALL_64_after_hwframe
        mmap64
        -                irqbalance (730)

After:
  # ./capable -UKv
    TIME     UID   PID     COMM             CAP     NAME                 AUDIT   VERDICT
    01:56:37 0     730     irqbalance       21      CAP_SYS_ADMIN        0       deny
        #0  0xffffffff81447dc6 cap_vm_enough_memory+0x26
        #1  0xffffffff8144a94f security_vm_enough_memory_mm+0x2f
        #2  0xffffffff812576e3 mmap_region+0x103
        #3  0xffffffff8125837e do_mmap+0x3de
        #4  0xffffffff8122c41c vm_mmap_pgoff+0xdc
        #5  0xffffffff81dc3be0 do_syscall_64+0x50
        #6  0xffffffff81e0011b entry_SYSCALL_64_after_hwframe+0x63
        #7  0x00007f3036e9e9ca mmap64+0xa (/lib/x86_64-linux-gnu/libc-2.19.so+0xf49ca)
        -                irqbalance (730)
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3 participants