<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - kernel BUG at fs/ext4/inode.c:2721!" href="https://bugs.freedesktop.org/show_bug.cgi?id=112012#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - kernel BUG at fs/ext4/inode.c:2721!" href="https://bugs.freedesktop.org/show_bug.cgi?id=112012">bug 112012</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>(In reply to Robert Holmes from <a href="show_bug.cgi?id=112012#c0">comment #0</a>) > Now, the reason I am reporting this on this bug tracker is that I've > bisected this issue (more precisely, the first WARNING right after boot) to > the following commit: > <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/">https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/</a> > ?h=linux-5.3.y&id=0bd6cb6b58f7332c61cef2e4ae48db1ca9910b6b Yikes. That shows that code was inherently more buggy than I thought, as it was causing us to drop writes to pages we didn't own (but thought we did). The root cause of the warn and ext4 bug is the lack of lock_page around set_page_dirty in userptr_put_pages. We tried putting a lock there, but we recurse into userptr_put_pages from underneath locked pages... There is a plan afoot to replace this interface with HMM in the hope that it makes the integration between the GPU and user pages much nicer and in the process resolve these mistakes.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>