On Fri, Jul 29, 2016 at 11:43:29AM -0400, Jeff Mahoney wrote: > On 6/6/16 10:13 AM, Jeff Mahoney wrote: > > On 6/6/16 7:47 AM, Adam Borowski wrote: > >> Hi! > >> I just got this thrice, in 4.7-rc1 and 4.7-rc2: > >> > >> [ 1836.672368] ------------[ cut here ]------------ > >> [ 1836.672382] WARNING: CPU: 1 PID: 16348 at fs/btrfs/inode.c:9820 btrfs_rename2+0xcd2/0x2a50 > >> [ 1836.672385] BTRFS: Transaction aborted (error -2) > >> [ 1836.672396] CPU: 1 PID: 16348 Comm: gcc-6 Tainted: P O 4.7.0-rc2-debug+ #3 > >> [ 1836.672415] Call Trace: > >> [ 1836.672423] [<ffffffff8165be6d>] dump_stack+0x4e/0x71 > >> [ 1836.672429] [<ffffffff81110c1c>] __warn+0x10c/0x150 > >> [ 1836.672433] [<ffffffff81110caa>] warn_slowpath_fmt+0x4a/0x50 > >> [ 1836.672437] [<ffffffff814f4842>] btrfs_rename2+0xcd2/0x2a50 > >> [ 1836.672443] [<ffffffff814dfcfb>] ? btrfs_permission+0x5b/0xc0 > >> [ 1836.672448] [<ffffffff81d288c8>] ? down_write+0x18/0x60 > >> [ 1836.672453] [<ffffffff8133a0cc>] vfs_rename+0x7cc/0xc30 > >> [ 1836.672457] [<ffffffff8133dc8b>] SyS_rename+0x32b/0x420 > >> [ 1836.672461] [<ffffffff81d2ab9f>] entry_SYSCALL_64_fastpath+0x17/0x93 > >> [ 1836.672464] ---[ end trace 6405b6e3d0e6c945 ]--- > >> [ 1836.672468] BTRFS warning (device sda1): btrfs_rename:9820: Aborting unused transaction(No such entry). > >> [ 1836.675505] BTRFS warning (device sda1): btrfs_rename:9820: Aborting unused transaction(No such entry). > >> <repeated 1152 times> > > > > Oh, interesting. We're seeing this on our 4.4-based kernels as well but > > only on arm64. That it's triggering on x86_64 is a good data point. > > I'm hunting this one today. > > I was finally able to track down what this was on arm64, and I'm afraid > the news won't help you much. It was a bug in gcc 4.8.5 instruction > scheduling around function return that caused the stack pointer to be > restored to the position at the beginning of the function while the > stack was still being used via a separate register. If an interrupt > arrived between those two instructions, you'd get stack corruption that > would present as bad hash values. > > Are you still able to reproduce this on x86_64? Nope, not in quite a while. I haven't used middle 4.7 rcs so I don't know when it went away. I use gcc-6, too. -- An imaginary friend squared is a real enemy. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
