On Mon, Jul 31, 2023 at 08:40:24PM +0100, Lorenzo Stoakes wrote: > On Mon, Jul 31, 2023 at 09:24:50PM +0200, David Hildenbrand wrote: > > On 31.07.23 21:21, Lorenzo Stoakes wrote: > > > On Mon, Jul 24, 2023 at 08:23:55AM +0200, David Hildenbrand wrote: > > > > Hi, > > > > > > > > > > > > > > I met this too when I executed below command to trigger a kcore reading. > > > > > I wanted to do a simple testing during system running and got this. > > > > > > > > > > makedumpfile --mem-usage /proc/kcore > > > > > > > > > > Later I tried your above objdump testing, it corrupted system too. > > > > > > > > > > > > > What do you mean with "corrupted system too" -- did it not only fail to > > > > dump the system, but also actually harmed the system? > > > > > > > > @Lorenzo do you plan on reproduce + fix, or should we consider reverting > > > > that change? > > > > > > > > -- > > > > Cheers, > > > > > > > > David / dhildenb > > > > > > > > > > Apologies I mised this, I have been very busy lately not least with book :) > > > > > > Concerning, I will take a look as I get a chance. I think the whole series > > > would have to be reverted which would be... depressing... as other patches > > > in series eliminates the bounce buffer altogether. > > > > > > > I spotted > > > > https://lkml.kernel.org/r/069dd40aa71e634b414d07039d72467d051fb486.camel@xxxxxx > > > > Find that slightly confusing, they talk about just reveritng the patch but then > also add a kern_addr_valid()? > > I'm also confused about people talking about just reverting the patch, as > 4c91c07c93bb drops the bounce buffer altogether... presumably they mean > reverting both? > > Clearly this is an arm64 thing (obviously), I have some arm64 hardware let me > see if I can repro... I see the issue on x86 > > Baoquan, Jiri - are you reverting more than just the one commit? And does doing > this go from not working -> working? Or from not working (worst case oops) -> > error? yes, I used to revert all 4 patches I did quick check and had to revert 2 more patches to get clean revert 38b138abc355 Revert "fs/proc/kcore: avoid bounce buffer for ktext data" e2c3b418d365 Revert "fs/proc/kcore: convert read_kcore() to read_kcore_iter()" d8bc432cb314 Revert "iov_iter: add copy_page_to_iter_nofault()" bf2c6799f68c Revert "iov_iter: Kill ITER_PIPE" ccf4b2c5c5ce Revert "mm: vmalloc: convert vread() to vread_iter()" de400d383a7e Revert "mm/vmalloc: replace the ternary conditional operator with min()" jirka
