Messages in this thread | | | From | Robert Richter <> | Subject | Re: linuxnext-2019127 edac warns (was Re: edac KASAN warning in experimental arm64 allmodconfig boot) | Date | Mon, 2 Dec 2019 11:46:39 +0000 |
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On 02.12.19 10:23:29, John Garry wrote: > On 28/11/2019 21:12, Robert Richter wrote: > > On 27.11.19 17:07:33, John Garry wrote: > > > [ 22.104498] BUG: KASAN: use-after-free in > > > edac_remove_sysfs_mci_device+0x148/0x180 > > > > It is triggered in edac_remove_sysfs_mci_device(). > > > > device_unregister(&dimm->dev) not only removes the sysfs entry, it > > also frees the dimm struct in dimm_attr_release(). When incrementing > > the loop in mci_for_each_dimm(), the dimm struct is accessed again > > which causes the use-after-free. But, the dimm struct shouln'd be > > released here already. > > > > edac_remove_sysfs_mci_device() should not release the devices at this > > point. We need clean release functions for mci and dimm_info and > > refcounts to protect pdev/dev mappings. And mci_for_each_dimm() must > > be checked how it handles device removals and if it is safe. > > > > Let's see how this can be fixed. > > > > Thanks for reporting the issue. > > Fine, and would any fix also deal with the v5.4 mem leak which I mentioned > also?
Yes, I have identified the leaks:
# grep edac /sys/kernel/debug/kmemleak | sort | uniq -c 1 [<000000003c0f58f9>] edac_mc_alloc+0x3bc/0x9d0 # mci->csrows 16 [<00000000bb932dc0>] edac_mc_alloc+0x49c/0x9d0 # csr->channels 16 [<00000000e2734dba>] edac_mc_alloc+0x518/0x9d0 # csr->channels[chn] 1 [<00000000eb040168>] edac_mc_alloc+0x5c8/0x9d0 # mci->dimms 34 [<00000000ef737c29>] ghes_edac_register+0x1c8/0x3f8 # see edac_mc_alloc()
Thanks,
-Robert
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