Hi Peter, I see the following runtime warning when running a 44x/virtex5_defconfig image in qemu (virtex-ml507).
refcount_t: underflow; use-after-free. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at lib/refcount.c:128 refcount_sub_and_test+0x90/0xd0 Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 4.10.0-next-20170227 #1 task: cf81d5a0 task.stack: cf81e000 NIP: c02100e0 LR: c02100e0 CTR: c0279970 REGS: cf81fc90 TRAP: 0700 Not tainted (4.10.0-next-20170227) MSR: 00029000 <CE,EE,ME> CR: 24000022 XER: 00000000 GPR00: c02100e0 cf81fd40 cf81d5a0 00000026 00000000 00000000 c027a3d0 00000000 GPR08: c05403bc 00000800 00000000 00000000 24000024 00000000 c0001ad0 00000000 GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 c054b3c0 c0550000 GPR24: 00000000 00000000 cf948010 00000015 00000000 00000000 cf948000 cfb1c0e8 NIP [c02100e0] refcount_sub_and_test+0x90/0xd0 LR [c02100e0] refcount_sub_and_test+0x90/0xd0 Call Trace: [cf81fd40] [c02100e0] refcount_sub_and_test+0x90/0xd0 (unreliable) [cf81fd50] [c01f6564] kobject_put+0x34/0x90 [cf81fd60] [c02ac240] ace_probe+0x410/0x450 [cf81fda0] [c0293684] platform_drv_probe+0x44/0xc0 [cf81fdc0] [c0291494] driver_probe_device+0x234/0x340 [cf81fdf0] [c029166c] __driver_attach+0xcc/0xd0 [cf81fe10] [c028eff8] bus_for_each_dev+0x68/0xc0 [cf81fe40] [c0290838] bus_add_driver+0x208/0x280 [cf81fe60] [c0292198] driver_register+0x88/0x140 [cf81fe70] [c050be10] ace_init+0x48/0xa4 [cf81fe90] [c0001350] do_one_initcall+0x40/0x180 [cf81fef0] [c04f2ae0] kernel_init_freeable+0x134/0x1cc [cf81ff30] [c0001ae4] kernel_init+0x14/0x110 [cf81ff40] [c000c3d0] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 40a2fff0 7f884840 7d094378 419e0044 2f89ffff 7d434850 7f0a4840 419e0018 4099ffd0 3c60c04b 386393f0 4820e99d <0fe00000> 80010014 38600000 38210010 ---[ end trace 17bd7014e44a5b26 ]--- xsysace 83600000.sysace: xsysace: error initializing device at 0x83600000 xsysace 83600000.sysace: could not initialize device, err=-12 xsysace: probe of 83600000.sysace failed with error -12 Xilinx SystemACE device driver, major=254 The complete log is available at http://kerneltests.org/builders/qemu-ppc-next/builds/590/steps/qemubuildcommand/logs/stdio Bisect points to commit 29dee3c03abc ("locking/refcounts: Out-of-line everything'); bisect log is attached. Reverting this commit fixes the problem. Please let me know if there is anything I can do to help tracking down the problem. [ Maybe there is a bug in the ace driver's error handler, but why is it only seen with your patch applied ? ] Guenter --- # bad: [2b9bda0679b5b4481396190d2f482fb9b31984f5] Revert "objtool: Improve detection of BUG() and other dead ends" # good: [c470abd4fde40ea6a0846a2beab642a578c0b8cd] Linux 4.10 git bisect start 'HEAD' 'v4.10' # good: [caa59428971d5ad81d19512365c9ba580d83268c] Merge tag 'staging-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging git bisect good caa59428971d5ad81d19512365c9ba580d83268c # good: [d5500a074741b78b7f778b4ab3415d5ecdcda0a7] Merge tag 'usercopy-v4.11-rc1.fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux git bisect good d5500a074741b78b7f778b4ab3415d5ecdcda0a7 # good: [5d8a00eee2ed2e548a5d21b0edf495f3f7bf8bb4] Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux git bisect good 5d8a00eee2ed2e548a5d21b0edf495f3f7bf8bb4 # good: [017bfb6c372fa793cdb09828597a464fa24e0ea7] Merge remote-tracking branch 'jfs/jfs-next' git bisect good 017bfb6c372fa793cdb09828597a464fa24e0ea7 # bad: [e2a95a3fe9e9586df29e8d673dc8cdd36ed6158b] Merge remote-tracking branch 'edac/linux_next' git bisect bad e2a95a3fe9e9586df29e8d673dc8cdd36ed6158b # good: [736e441efdafdbf0bb32732d87e00b8ba7f75260] Merge remote-tracking branch 'thermal/next' git bisect good 736e441efdafdbf0bb32732d87e00b8ba7f75260 # good: [5bd695c24b294b482d86d352a4a0c7ba2059dcff] Merge remote-tracking branch 'block/for-next' git bisect good 5bd695c24b294b482d86d352a4a0c7ba2059dcff # good: [690962e72babac64c8240071e106d2c3e8d08306] Merge remote-tracking branch 'spi/for-next' git bisect good 690962e72babac64c8240071e106d2c3e8d08306 # bad: [462a53b1a2f984a8c8c0aade1c461ce9ea156d5b] Merge branch 'perf/urgent' git bisect bad 462a53b1a2f984a8c8c0aade1c461ce9ea156d5b # good: [bb963e16507ca7670f0bb47ccaada8874b2ba6a1] perf utils: Check verbose flag properly git bisect good bb963e16507ca7670f0bb47ccaada8874b2ba6a1 # good: [7bbba0eb1af34694868d028b80475981f90e6bee] perf/core: Fix perf_event_enable_on_exec() timekeeping (again) git bisect good 7bbba0eb1af34694868d028b80475981f90e6bee # good: [1db159781cc7df093085ccaddc022beaaa9dd990] Merge branch 'core/urgent' git bisect good 1db159781cc7df093085ccaddc022beaaa9dd990 # bad: [318b1dedcd39012624f466d281627553e9fa2570] locking/refcounts: Add missing kernel.h header to have UINT_MAX defined git bisect bad 318b1dedcd39012624f466d281627553e9fa2570 # bad: [29dee3c03abce04cd527878ef5f9e5f91b7b83f4] locking/refcounts: Out-of-line everything git bisect bad 29dee3c03abce04cd527878ef5f9e5f91b7b83f4 # first bad commit: [29dee3c03abce04cd527878ef5f9e5f91b7b83f4] locking/refcounts: Out-of-line everything
