panic: Memory modified after free

[Andriy Gapon]

On 08/10/2019 03:39, Yuri Pankov wrote:
> (posting to fs@ as backtrace suggests zfs)
> 
> Started seeing the following panic (sometimes reproducible, so can't point specific revision or time range) untaring an archive over ssh into my home directory on zfs:
> 
> panic: Memory modified after free 0xfffff80404cff000(4096) val=dead40de @ 0xfffff80404cff694
> 
> cpuid = 4
> time = 1570493241
> KDB: stack backtrace:
> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00df912650
> vpanic() at vpanic+0x19d/frame 0xfffffe00df9126a0
> panic() at panic+0x43/frame 0xfffffe00df912700
> trash_ctor() at trash_ctor+0x49/frame 0xfffffe00df912710
> uma_zalloc_arg() at uma_zalloc_arg+0xa24/frame 0xfffffe00df9127a0
> abd_alloc() at abd_alloc+0x152/frame 0xfffffe00df9127f0
> arc_hdr_alloc_pabd() at arc_hdr_alloc_pabd+0x166/frame 0xfffffe00df912820
> arc_write_ready() at arc_write_ready+0x463/frame 0xfffffe00df912860
> zio_ready() at zio_ready+0xde/frame 0xfffffe00df9128a0
> zio_execute() at zio_execute+0x17c/frame 0xfffffe00df9128e0
> taskqueue_run_locked() at taskqueue_run_locked+0x10c/frame 0xfffffe00df912940
> taskqueue_thread_loop() at taskqueue_thread_loop+0x88/frame 0xfffffe00df912970
> fork_exit() at fork_exit+0x84/frame 0xfffffe00df9129b0
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe00df9129b0
> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
> 
> Full text dump is at https://people.freebsd.org/~yuripv/core.txt.0.
> 
> Real problem or failing hardware (memory?)?

Given a single bit difference between 0xdead40de and 0xdeadc0de, it can be
either.  If the memory is not ECC, then I would assume a hardware problem first.


-- 
Andriy Gapon