On Tue, May 19, 2020 at 03:18:13PM -0700, Thiago Macieira wrote: > > I really wonder about the missing couple of syscalls in your strace, though; > > could you verify that they _are_ missing and see what the fix above does to > > your testcase? > > Looking at my terminal backtrace, I might have made a copy & paste mistake of > the trace while flipping pages. Unfortunately, the trace file I had in /tmp > was lost because I needed to reboot the machine. The other traces I have in my > terminal show: > > fcntl(2, F_DUPFD, 134217728) = 134217728 > close(134217728) = 0 > fcntl(2, F_DUPFD, 268435456) = 268435456 > close(268435456) = 0 > fcntl(2, F_DUPFD, 536870912) = 536870912 > close(536870912) = 0 > write(1, "success\n", 8) = ? > ^C^Czsh: killed sudo strace ./dupfd-bug > > I had to killall -9 strace at this point. See the attached oops. BS values in the array of struct file pointers due to the problem above. And very likely a memory corruption as well. > Then I insisted: > > fcntl(2, F_DUPFD, 67108864) = 67108864 > close(67108864) = 0 > fcntl(2, F_DUPFD, 134217728) = 134217728 > close(134217728) = 0 > fcntl(2, F_DUPFD, 268435456Shared connection to <REDACTED> closed. > > At this point, I need to drive to the office to reboot the machine. Building > the kernel and testing will take a few days. > > Note to self: don't play with possible kernel bugs without a VM. ... at least not without remote console, complete with ability to powercycle the box.
