On a 7.1 or current- kernel with TMPFS enabled, the following panic occurs.
# mount -t tmpfs swap /mnt
# cd /mnt
# echo test > testfile # A new file can be created normally.
# cat testfile
test
# Output redirection to an already
# echo test2 > testfile # existing file causes panic.
panic: kernel diagnostic assertion "rw_write_held(uobj->vmobjlock)" failed:
fil
e "/usr/src/sys/uvm/uvm_aobj.c", line 876
Stopped at db_enter+0x10: popq %rbp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
*184475 41532 0 0x100003 0 0 ksh
db_enter() at db_enter+0x10
panic(ffffffff81f10681) at panic+0xb8
__assert(ffffffff81f83ea0,ffffffff81f05a10,36c,ffffffff81f1e964) at
__assert+0x
25
uao_flush(fffffd803f12fe58,0,1000,8) at uao_flush+0x24e
uao_shrink_array(fffffd803f12fe58,0) at uao_shrink_array+0x77
tmpfs_reg_resize(fffffd800eabe4a0,0) at tmpfs_reg_resize+0x167
tmpfs_chsize(fffffd800eabe4a0,0,fffffd803f7d9720,ffff8000ffff5ce8) at
tmpfs_chs
ize+0xd9
tmpfs_setattr(ffff800014da7d48) at tmpfs_setattr+0xe6
VOP_SETATTR(fffffd800eabe4a0,ffff800014da7da0,fffffd803f7d9720,ffff8000ffff5ce8
) at VOP_SETATTR+0x4b
vn_open(ffff800014da7f60,602,1a4) at vn_open+0x25a
doopenat(ffff8000ffff5ce8,ffffff9c,73d81734350,601,1b6,ffff800014da8130) at
doo
penat+0x1cd
syscall(ffff800014da81a0) at syscall+0x324
Xsyscall() at Xsyscall+0x128
endbofokernel
endbtrace-frame: 0x7f7fffff3940, count: 2
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.e-Insufficient info makes it difficult to find and fix bugs.
ddb>
The kernel config files are as follows.
# diff -u /usr/src/sys/conf/GENERIC /usr/src/sys/conf/GENERIC_TMPFS
--- /usr/src/sys/conf/GENERIC Wed Apr 6 00:14:59 2022
+++ /usr/src/sys/conf/GENERIC_TMPFS Sat Apr 16 14:26:14 2022
@@ -40,7 +40,7 @@
option UDF # UDF (DVD) file system
option MSDOSFS # MS-DOS file system
option FIFO # FIFOs; RECOMMENDED
-#option TMPFS # efficient memory file system
+option TMPFS # efficient memory file system
option FUSE # FUSE
option SOCKET_SPLICE # Socket Splicing for TCP and UDP
# diff -u /usr/src/sys/arch/amd64/conf/GENERIC
/usr/src/sys/arch/amd64/conf/GENERIC_TMPFS
--- /usr/src/sys/arch/amd64/conf/GENERIC Wed Mar 9 00:08:01 2022
+++ /usr/src/sys/arch/amd64/conf/GENERIC_TMPFS Sat Apr 16 14:25:37 2022
@@ -10,7 +10,7 @@
# device.
machine amd64
-include "../../../conf/GENERIC"
+include "../../../conf/GENERIC_TMPFS"
maxusers 80 # estimated number of users
option USER_PCICONF # user-space PCI configuration
