^
ffffc90000cf2080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90000cf2100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
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^
ffffc90000cf2080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90000cf2100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
On Thu, 20 Jan 2022 at 15:17, syzbot
[off-list ref] wrote:
syzbot suspects this issue was fixed by commit:
commit 218d747a4142f281a256687bb513a135c905867b
Author: John Fastabend [off-list ref]
Date: Tue Jan 4 21:46:45 2022 +0000
bpf, sockmap: Fix double bpf_prog_put on error case in map_link
I can confirm the above commit fixes the issue, but it references a
slightly different report. Looks like the only difference is
__bpf_prog_put instead of bpf_prog_put:
KASAN: vmalloc-out-of-bounds Read in __bpf_prog_put
KASAN: vmalloc-out-of-bounds Read in bpf_prog_put
However, looking at the stack traces for the two bugs shows that
__bpf_prog_put() is really the location for both reports, see:
https://syzkaller.appspot.com/bug?id=797cd651dd0d9bd921e4fa51b792f5afdc3f390f
kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 mm/kasan/report.c:450
__bpf_prog_put.constprop.0+0x1dd/0x220 kernel/bpf/syscall.c:1812
kernel/bpf/syscall.c:1812
bpf_prog_put kernel/bpf/syscall.c:1829 [inline]
bpf_prog_put kernel/bpf/syscall.c:1829 [inline] kernel/bpf/syscall.c:1837
vs.
https://syzkaller.appspot.com/bug?extid=bb73e71cf4b8fd376a4f
kasan_report+0x19a/0x1f0 mm/kasan/report.c:450 mm/kasan/report.c:450
__bpf_prog_put kernel/bpf/syscall.c:1812 [inline]
__bpf_prog_put kernel/bpf/syscall.c:1812 [inline] kernel/bpf/syscall.c:1829
bpf_prog_put+0x8c/0x4f0 kernel/bpf/syscall.c:1829 kernel/bpf/syscall.c:1829
Looks to me like the compiler's inlining decision caused syzbot to see
__bpf_prog_put() instead of bpf_prog_put(), but I can't tell if it's
because it got inlined or because of the .constprop.0 suffix... I
guess syzbot skips the [inline] entries when deciding which function
to report the bug in?
In any case:
#syz dup: KASAN: vmalloc-out-of-bounds Read in bpf_prog_put
Vegard
On Mon, 24 Jan 2022 at 12:42, Vegard Nossum [off-list ref] wrote:
On Thu, 20 Jan 2022 at 15:17, syzbot
[off-list ref] wrote:
quoted
syzbot suspects this issue was fixed by commit:
commit 218d747a4142f281a256687bb513a135c905867b
Author: John Fastabend [off-list ref]
Date: Tue Jan 4 21:46:45 2022 +0000
bpf, sockmap: Fix double bpf_prog_put on error case in map_link
I can confirm the above commit fixes the issue, but it references a
slightly different report. Looks like the only difference is
__bpf_prog_put instead of bpf_prog_put:
KASAN: vmalloc-out-of-bounds Read in __bpf_prog_put
KASAN: vmalloc-out-of-bounds Read in bpf_prog_put
However, looking at the stack traces for the two bugs shows that
__bpf_prog_put() is really the location for both reports, see:
https://syzkaller.appspot.com/bug?id=797cd651dd0d9bd921e4fa51b792f5afdc3f390f
kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 mm/kasan/report.c:450
__bpf_prog_put.constprop.0+0x1dd/0x220 kernel/bpf/syscall.c:1812
kernel/bpf/syscall.c:1812
bpf_prog_put kernel/bpf/syscall.c:1829 [inline]
bpf_prog_put kernel/bpf/syscall.c:1829 [inline] kernel/bpf/syscall.c:1837
vs.
https://syzkaller.appspot.com/bug?extid=bb73e71cf4b8fd376a4f
kasan_report+0x19a/0x1f0 mm/kasan/report.c:450 mm/kasan/report.c:450
__bpf_prog_put kernel/bpf/syscall.c:1812 [inline]
__bpf_prog_put kernel/bpf/syscall.c:1812 [inline] kernel/bpf/syscall.c:1829
bpf_prog_put+0x8c/0x4f0 kernel/bpf/syscall.c:1829 kernel/bpf/syscall.c:1829
Looks to me like the compiler's inlining decision caused syzbot to see
__bpf_prog_put() instead of bpf_prog_put(), but I can't tell if it's
because it got inlined or because of the .constprop.0 suffix... I
guess syzbot skips the [inline] entries when deciding which function
to report the bug in?
Not sure if you are still interested in this or not...
But, yes, it's inline frames that are a problem, ".constprop.0" should
be stripped.
syzkaller parses non-symbolized kernel output w/o inlined frames to
extract the title. This was a very early decision, not sure if it's
the right one or not. On the other hand using inline frames can cause
attribution to all the common one-liners.
Now it's somewhat hard to change b/c if we change it, new crashes will
be parsed differently and it will cause a storm of duplicates for
already reported bugs.
In any case:
#syz dup: KASAN: vmalloc-out-of-bounds Read in bpf_prog_put
Vegard