Date: Sun, 29 Dec 2019 15:17:58 -0700 From: Ian Lepore <ian@freebsd.org> To: Hans Petter Selasky <hps@selasky.org>, Mark Millard <marklmi@yahoo.com>, FreeBSD Current <freebsd-current@freebsd.org>, freebsd-hackers@freebsd.org, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: head -r356109 on 32-bit powerpc (old PowerMac): Memory modified after free during late-stage of boot, most recently used by bus-sc Message-ID: <e01b3ad0f3b4318f800df543fd6361302ffaef72.camel@freebsd.org> In-Reply-To: <42bf7ff5-1279-28cb-5b4b-a0335e819a3a@selasky.org> References: <28FD8632-AC91-40D7-B6E7-36E304D37794.ref@yahoo.com> <28FD8632-AC91-40D7-B6E7-36E304D37794@yahoo.com> <42bf7ff5-1279-28cb-5b4b-a0335e819a3a@selasky.org>
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On Sun, 2019-12-29 at 23:04 +0100, Hans Petter Selasky wrote: > On 2019-12-29 22:53, Mark Millard via freebsd-hackers wrote: > > 0xd2630510: at uma_zalloc_arg+0x1b4 > > 0xd2630540: at malloc+0xfc > > 0xd2630580: at alloc_bounce_pages+0x7c > > 0xd26305c0: at bus_dmamap_create+0x1e8 > > Do you know what drivers are using bounce pages? > > busdma isn't the culprit here. It was trying to allocate memory and the uma code found a block that was free and checked it before handing it out, and discovered that it had been modified after being freed. Before being freed, the memory was last used as the softc for some device (perhaps only during probing of a device that never attached). That device would most likely be the culprit (or a wild-pointer write hit that block). -- Ian
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