On Sun, Sep 17, 2023 at 11:10:32AM +0200, Peter Zijlstra wrote: > On Sat, Sep 16, 2023 at 02:55:47PM +0800, Baokun Li wrote: > > On 2023/9/13 16:59, Yi Zhang wrote: > > > The issue still can be reproduced on the latest linux tree[2]. > > > To reproduce I need to run about 1000 times blktests block/001, and > > > bisect shows it was introduced with commit[1], as it was not 100% > > > reproduced, not sure if it's the culprit? > > > > > > > > > [1] 9257959a6e5b locking/atomic: scripts: restructure fallback ifdeffery > > Hello, everyone！ > > > > We have confirmed that the merge-in of this patch caused hlist_bl_lock > > (aka, bit_spin_lock) to fail, which in turn triggered the issue above. > > > [root@localhost ~]# insmod mymod.ko > > [ 37.994787][ T621] >>> a = 725, b = 724 > > [ 37.995313][ T621] ------------[ cut here ]------------ > > [ 37.995951][ T621] kernel BUG at fs/mymod/mymod.c:42! > > [r[ oo 3t7@.l996o4c61al]h[o s T6t21] ~ ]#Int ernal error: Oops - BUG: > > 00000000f2000800 [#1] SMP > > [ 37.997420][ T621] Modules linked in: mymod(E) > > [ 37.997891][ T621] CPU: 9 PID: 621 Comm: bl_lock_thread2 Tainted: > > G E 6.4.0-rc2-00034-g9257959a6e5b-dirty #117 > > [ 37.999038][ T621] Hardware name: linux,dummy-virt (DT) > > [ 37.999571][ T621] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS > > BTYPE=--) > > [ 38.000344][ T621] pc : increase_ab+0xcc/0xe70 [mymod] > > [ 38.000882][ T621] lr : increase_ab+0xcc/0xe70 [mymod] > > [ 38.001416][ T621] sp : ffff800008b4be40 > > [ 38.001822][ T621] x29: ffff800008b4be40 x28: 0000000000000000 x27: > > 0000000000000000 > > [ 38.002605][ T621] x26: 0000000000000000 x25: 0000000000000000 x24: > > 0000000000000000 > > [ 38.003385][ T621] x23: ffffd9930c698190 x22: ffff800008a0ba38 x21: > > 0000000000000001 > > [ 38.004174][ T621] x20: ffffffffffffefff x19: ffffd9930c69a580 x18: > > 0000000000000000 > > [ 38.004955][ T621] x17: 0000000000000000 x16: ffffd9933011bd38 x15: > > ffffffffffffffff > > [ 38.005754][ T621] x14: 0000000000000000 x13: 205d313236542020 x12: > > ffffd99332175b80 > > [ 38.006538][ T621] x11: 0000000000000003 x10: 0000000000000001 x9 : > > ffffd9933022a9d8 > > [ 38.007325][ T621] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : > > ffffd993320b5b40 > > [ 38.008124][ T621] x5 : ffff0001f7d1c708 x4 : 0000000000000000 x3 : > > 0000000000000000 > > [ 38.008912][ T621] x2 : 0000000000000000 x1 : 0000000000000000 x0 : > > 0000000000000015 > > [ 38.009709][ T621] Call trace: > > [ 38.010035][ T621] increase_ab+0xcc/0xe70 [mymod] > > [ 38.010539][ T621] kthread+0xdc/0xf0 > > [ 38.010927][ T621] ret_from_fork+0x10/0x20 > > [ 38.011370][ T621] Code: 17ffffe0 90000020 91044000 9400000d (d4210000) > > [ 38.012067][ T621] ---[ end trace 0000000000000000 ]--- > > Is this arm64 or something? You seem to have forgotten to mention what > platform you're using. Is that an LSE or LLSC arm64 ? Anyway, it seems that ARM64 shouldn't be using the fallback as it does everything itself. Mark, can you have a look please? At first glance the atomic64_fetch_or_acquire() that's being used by generic bitops/lock.h seems in order..
