Messages in this thread | | | Date | Thu, 29 Sep 2011 20:43:34 -0500 | From | Jonathan Nieder <> | Subject | [PATCH 3.1-rc8 0/2] Two false positives from debugging tools (lockdep, kmemleak) |
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Hi,
Especially during the -rc period, it is nice to be able to take advantage of lockdep and kmemleak to find bugs. False positives make it harder to find real problems amid the noise.
At boot time, I get:
| allocated 14680064 bytes of page_cgroup | please try 'cgroup_disable=memory' option if you don't want memory cgroups | kmemleak: Trying to color unknown object at 0xffff88006f500000 as Grey | Pid: 0, comm: swapper Not tainted 3.1.0-rc8-00031-gd5767c53535a #12 | Call Trace: | [<ffffffff810f8637>] paint_ptr+0x56/0x8e | [<ffffffff812e336c>] kmemleak_not_leak+0x23/0x42 | [<ffffffff816a00d5>] kmemleak_init+0x1db/0x23a | [<ffffffff81686ad2>] start_kernel+0x31c/0x3b1 | [<ffffffff816862a8>] x86_64_start_reservations+0xaf/0xb3 | [<ffffffff81686140>] ? early_idt_handlers+0x140/0x140 | [<ffffffff816863ae>] x86_64_start_kernel+0x102/0x111 | kmemleak: Trying to color unknown object at 0xffff88006f600000 as Grey [and so on, for 13 addresses in all]
Also:
| [ 222.425445] systemd-logind/908 is trying to acquire lock: | [ 222.425447] (&ep->mtx){+.+.+.}, at: [<ffffffff8112da68>] ep_scan_ready_list+0x3c/0x1a7 | [ 222.425456] | [ 222.425457] but task is already holding lock: | [ 222.425459] (&ep->mtx){+.+.+.}, at: [<ffffffff8112dfd8>] sys_epoll_ctl+0x11d/0x520
Luckily both false positives seem to be known and well understood. The first of the patches below (the kmemleak one) seems to have fallen under the radar --- I can't even find it in linux-next. The second (the lockdep one) is taken from akpm's -mm patchset.
Thoughts?
Nelson Elhage (1): epoll: fix spurious lockdep warnings
Steven Rostedt (1): cgroup/kmemleak: Annotate alloc_page() for cgroup allocations
fs/eventpoll.c | 25 ++++++++++++++++++------- mm/page_cgroup.c | 7 +++++-- 2 files changed, 23 insertions(+), 9 deletions(-)
-- 1.7.7.rc1
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