On 10/13/18 12:56 AM, Andrew Morton wrote: > (cc linux-mm, argh) > > On Fri, 12 Oct 2018 15:55:33 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > >> >> (switched to email. Please respond via emailed reply-to-all, not via the >> bugzilla web interface). >> >> Vlastimil, it looks like your August 21 smaps changes are failing. >> This one is pretty urgent, please. Thanks, will look in few hours. Glad that there will be rc8... >> Leonardo (yes?): thanks for reporting. Very helpful. >> >> On Thu, 11 Oct 2018 18:13:31 +0000 bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: >> >>> https://bugzilla.kernel.org/show_bug.cgi?id=201377 >>> >>> Bug ID: 201377 >>> Summary: Kernel BUG under memory pressure: unable to handle >>> kernel NULL pointer dereference at 00000000000000f0 >>> Product: Memory Management >>> Version: 2.5 >>> Kernel Version: 4.19-rc7 >>> Hardware: All >>> OS: Linux >>> Tree: Mainline >>> Status: NEW >>> Severity: normal >>> Priority: P1 >>> Component: Other >>> Assignee: akpm@xxxxxxxxxxxxxxxxxxxx >>> Reporter: leozinho29_eu@xxxxxxxxxxx >>> Regression: No >>> >>> Created attachment 278997 >>> --> https://bugzilla.kernel.org/attachment.cgi?id=278997&action=edit >>> dmesg and kernel config >>> >>> I'm using Xubuntu 18.04 and I noticed that under memory pressure the script >>> from https://github.com/pixelb/ps_mem.git (HEAD >>> 1ed0bc5519d889d58235f2c35db01e4ede0d8231is) causing a kernel BUG and locking a >>> CPU. On dmesg the following appears: >>> >>> BUG: unable to handle kernel NULL pointer dereference at 00000000000000f0 >>> >>> After this BUG the computer performance becomes greatly degraded, some software >>> do not close, some fail to open, some fail to work properly. As an example, >>> bash fails to autocomplete. >>> >>> Steps to reproduce: >>> >>> 1) Be under memory pressure. Using dd to write a large file at /dev/shm works >>> for this; >>> 2) Run the script from https://github.com/pixelb/ps_mem.git >>> >>> Expected result: script will print information and system will keep working >>> normally; >>> >>> Observed result: script is killed, kernel BUG happens, CPU get stuck and >>> computer presents problems. >>> >>> I did not observe this with 4.17.19, I'll bisect and see if I can find which >>> commit is causing this. >>> >>> I'm sorry if I'm reporting to the wrong product and component. >>> >>> -- >>> You are receiving this mail because: >>> You are the assignee for the bug.
