On Fri, Oct 28, 2022 at 06:18:36PM -0700, Eric Dumazet wrote: > On Fri, Oct 28, 2022 at 6:12 PM Oleksandr Tymoshenko <ovt@xxxxxxxxxx> wrote: > > > > Hello, > > > > This commit causes the following panic in kernel built with clang > > (GCC build is not affected): > > > > [ 8.320308] BUG: unable to handle page fault for address: ffffffff97216c6a [26/4066] > > [ 8.330029] #PF: supervisor write access in kernel mode > > [ 8.337263] #PF: error_code(0x0003) - permissions violation > > [ 8.344816] PGD 12e816067 P4D 12e816067 PUD 12e817063 PMD 800000012e2001e1 > > [ 8.354337] Oops: 0003 [#1] SMP PTI > > [ 8.359178] CPU: 2 PID: 437 Comm: curl Not tainted 5.4.220 #15 > > [ 8.367241] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 > > [ 8.378529] RIP: 0010:__do_once_slow_done+0xf/0xa0 > > [ 8.384962] Code: 1b 84 db 74 0c 48 c7 c7 80 ce 8d 97 e8 fa e9 4a 00 84 db 0f 94 c0 5b 5d c3 66 90 55 48 89 e5 41 57 41 56 > > 53 49 89 d7 49 89 f6 <c6> 07 01 48 c7 c7 80 ce 8d 97 e8 d2 e9 4a 00 48 8b 3d 9b de c9 00 > > [ 8.409066] RSP: 0018:ffffb764c02d3c90 EFLAGS: 00010246 > > [ 8.415697] RAX: 4f51d3d06bc94000 RBX: d474b86ddf7162eb RCX: 000000007229b1d6 > > [ 8.424805] RDX: 0000000000000000 RSI: ffffffff9791b4a0 RDI: ffffffff97216c6a > > [ 8.434108] RBP: ffffb764c02d3ca8 R08: 0e81c130f1159fc1 R09: 1d19d60ce0b52c77 > > [ 8.443408] R10: 8ea59218e6892b1f R11: d5260237a3c1e35c R12: ffff9c3dadd42600 > > [ 8.452468] R13: ffffffff97910f80 R14: ffffffff9791b4a0 R15: 0000000000000000 > > [ 8.461416] FS: 00007eff855b40c0(0000) GS:ffff9c3db7a80000(0000) knlGS:0000000000000000 > > [ 8.471632] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 8.478763] CR2: ffffffff97216c6a CR3: 000000022ded0000 CR4: 00000000000006a0 > > [ 8.487789] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > [ 8.496684] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > [ 8.505443] Call Trace: > > [ 8.508568] __inet_hash_connect+0x523/0x530 > > [ 8.513839] ? inet_hash_connect+0x50/0x50 > > [ 8.518818] ? secure_ipv4_port_ephemeral+0x69/0xe0 > > [ 8.525003] tcp_v4_connect+0x2c5/0x410 > > [ 8.529858] __inet_stream_connect+0xd7/0x360 > > [ 8.535329] ? _raw_spin_unlock+0xe/0x10 > > ... skipped ... > > > > > > The root cause is the difference in __section macro semantics between 5.4 and > > later LTS releases. On 5.4 it stringifies the argument so the ___done > > symbol is created in a bogus section ".data.once", with double quotes: > > > > % readelf -S vmlinux | grep data.once > > [ 5] ".data.once" PROGBITS ffffffff82216c6a 01416c6a > > Yes, this has been discovered earlier today. > > Look at Google-Bug-Id 256204637 It's a bit hard to see a google bug in public :( Why not talk about it here? > (include/linux/mmdebug.h has a similar issue) Is this an issue in Linus's tree? Should it be reverted there and/or in stable kernels too? what is recommended? thanks, greg k-h
