----- On Apr 8, 2019, at 11:21 AM, paulmck [email protected] wrote: > On Mon, Apr 08, 2019 at 10:57:50PM +0800, Rong Chen wrote: >> On Mon, Apr 08, 2019 at 07:30:37AM -0700, Paul E. McKenney wrote: >> > On Mon, Apr 08, 2019 at 09:56:10PM +0800, kernel test robot wrote: >> > > FYI, we noticed the following commit (built with gcc-7): >> > > >> > > commit: a365bb5f6eafb220a1448674054b05c250829313 ("srcu: Allocate >> > > per-CPU data >> > > for DEFINE_SRCU() in modules") >> > > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git >> > > tmp.2019.04.07a >> > > >> > > in testcase: leaking_addresses >> > > with following parameters: >> > > >> > > >> > > >> > > >> > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 >> > > -m 2G >> > > >> > > caused below changes (please refer to attached dmesg/kmsg for entire >> > > log/backtrace): >> > > >> > > >> > > +-------------------------------------------------+------------+------------+ >> > > | | a44a55abae | >> > > a365bb5f6e | >> > > +-------------------------------------------------+------------+------------+ >> > > | boot_successes | 0 | 3 >> > > | >> > > | boot_failures | 4 | 6 >> > > | >> > > | BUG:kernel_reboot-without-warning_in_test_stage | 4 | 6 >> > > | >> > > | leaking_addresses.proc.___srcu_struct_ptrs. | 0 | 6 >> > > | >> > > +-------------------------------------------------+------------+------------+ >> > >> > Please help me out here. Without this commit, the kernel never succeeds >> > in booting, but with it the kernel sometimes succeeds in booting? Or am >> > I misinterpreting the above table? >> > >> > Thanx, Paul >> >> Hi Paul, >> >> The message "kernel_reboot-without-warning_in_test_stage" is from 0day, >> leaking addresses generated many dmesgs, so 0day thought some bootings may >> failed. > [...] >> > >> > > [1 .rodata.cst16.POLY] 0xffffffffc0498360 >> > > [1 .rodata.cst32.byteshift_table] 0xffffffffc03f50f0 >> > > [19 __bug_table] 0xffffffffc02be184 >> > > [2 __tracepoints_ptrs] 0xffffffffc02f1cd0 >> > > [15 .smp_locks] 0xffffffffc042b2cc >> > > [1 .rodata.cst16.enc] 0xffffffffc0498420 >> > > [11 __ksymtab_gpl] 0xffffffffc042b028 >> > > [8 __ex_table] 0xffffffffc04f13f4 >> > > [1 .init.rodata] 0xffffffffc0316000 >> > > [36 .note.gnu.build-id] 0xffffffffc03ed000 >> > > [1 .rodata.cst16.dec] 0xffffffffc0498410 >> > > [16 .parainstructions] 0xffffffffc03ed940 >> > > [8 .text..refcount] 0xffffffffc04e2aaa >> > > [36 .gnu.linkonce.this_module] 0xffffffffc03f12c0 >> > > [2 __bpf_raw_tp_map] 0xffffffffc03054a0 >> > > [30 .orc_unwind_ip] 0xffffffffc03ee9f9 >> > > [8 .altinstr_replacement] 0xffffffffc0497372 >> > > [26 .rodata.str1.8] 0xffffffffc03ed1f0 >> > > [11 __verbose] 0xffffffffc05c9398 >> > > [1 .rodata.cst16.TWOONE] 0xffffffffc0498380 >> > > [1 uevent] KEY=402000000 3803078f800d001 feffffdfffefffff >> > > fffffffffffffffe >> > > [1 .rodata.cst16.ONE] 0xffffffffc04983e0 >> > > [8 .altinstructions] 0xffffffffc0498430 >> > > [36 modules] crct10dif_pclmul 16384 1 - Live 0xffffffffc03f4000 >> > > [1 ___srcu_struct_ptrs] 0xffffffffc03840d0 >> > >
This list of "leaked" memory seems to include the __tracepoint_ptrs as well. So at least you seem to have the same behavior as the tracepoint code, which was your source of inspiration for this implementation, which is a good start. So the remaining question is: is this memory allocated for module sections really leaked for each module, or is it an issue with memory allocation tracking ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
