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

From: Bert Karwatzki <[email-masked]>
Date: Fri, 14 Jun 2024 01:40:54 +0200

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.

Bert Karwatzki

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