Subject: Re: commit 1c29a32ce65f4cd0f1c causes Bad rss-counter state and firefox-esr crash in linux-next-20240613

From: Jiri Olsa <[email-masked]>
Date: Fri, 14 Jun 2024 09:54:35 +0200

On Fri, Jun 14, 2024 at 01:40:54AM +0200, Bert Karwatzki wrote:
> Since linux-next-20240613 firefox-esr crashes after several minutes of browsing
> giving the following error messages in dmesg:
> [ T2343] BUG: Bad rss-counter state mm:00000000babe0c39 type:MM_ANONPAGES val:86
> [ T4063] show_signal_msg: 16 callbacks suppressed
> [ T4063] Isolated Web Co[4063]: segfault at 396d1686c000 ip 0000396d1686c000 sp
> 00007ffd767b30a8 error 14 likely on CPU 7 (core 3, socket 0)
> [ T4063] Code: Unable to access opcode bytes at 0x396d1686bfd6.
> [ T4211] BUG: Bad rss-counter state mm:00000000cd9fc541 type:MM_ANONPAGES
> val:817
> [ T3798] BUG: Bad rss-counter state mm:00000000432d87c2 type:MM_ANONPAGES
> val:181
> [ T5548] BUG: Bad rss-counter state mm:00000000034aa27a type:MM_ANONPAGES
> val:242
> [ T3823] BUG: Bad rss-counter state mm:0000000099734197 type:MM_ANONPAGES
> val:137
> [    T1] BUG: Bad rss-counter state mm:000000005e5e2f2f type:MM_ANONPAGES val:28
> 
> (these are the error messages of several crashes and the error seems to affect
> other processes, too (T1))
> 
> The crash can be provoked to appear in ~1min by opening large numbers of tabs in
> firefox-esr (by holding pressing ctrl+t for some time). With this I bisected the
> error to commit "1c29a32ce65f mm/mmap: use split munmap calls for MAP_FIXED" and
> reverting this commit in linux-next-20240613 fixes the issue for me.

+1, bpf selftests are failing for me because mmap fails with:
  mmap(0x7f9361bc9000, 4096, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 4, 0) = -1 EBUSY (Device or resource busy)

did not get to the cause, but reverting the 1c29a32ce65f fixes it for me

thanks,
jirka

> 
> Bert Karwatzki
> 
> PS. Please CC me when answering, I'm not subscribed to the lists.
>