Hi, "Pankaj Raghav (Samsung)" <kernel@xxxxxxxxxxxxxxxx> writes: > From: Luis Chamberlain <mcgrof@xxxxxxxxxx> > > split_folio() and split_folio_to_list() assume order 0, to support > minorder for non-anonymous folios, we must expand these to check the > folio mapping order and use that. > > Set new_order to be at least minimum folio order if it is set in > split_huge_page_to_list() so that we can maintain minimum folio order > requirement in the page cache. > > Update the debugfs write files used for testing to ensure the order > is respected as well. We simply enforce the min order when a file > mapping is used. > > Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> > Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx> > Reviewed-by: Hannes Reinecke <hare@xxxxxxx> > Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> > Tested-by: David Howells <dhowells@xxxxxxxxxx> This causes the following warning on s390 with linux-next starting from next-20240827: [ 112.690518] BUG: Bad page map in process ksm01 pte:a5801317 pmd:99054000 [ 112.690531] page: refcount:0 mapcount:-1 mapping:0000000000000000 index:0x3ff86102 pfn:0xa5801 [ 112.690536] flags: 0x3ffff00000000004(referenced|node=0|zone=1|lastcpupid=0x1ffff) [ 112.690543] raw: 3ffff00000000004 0000001d47439e30 0000001d47439e30 0000000000000000 [ 112.690546] raw: 000000003ff86102 0000000000000000 fffffffe00000000 0000000000000000 [ 112.690548] page dumped because: bad pte [ 112.690549] addr:000003ff86102000 vm_flags:88100073 anon_vma:000000008c8e46e8 mapping:0000000000000000 index:3ff86102 [ 112.690553] file:(null) fault:0x0 mmap:0x0 read_folio:0x0 [ 112.690561] CPU: 1 UID: 0 PID: 604 Comm: ksm01 Not tainted 6.11.0-rc5-next-20240827-dirty #1441 [ 112.690565] Hardware name: IBM 3931 A01 704 (z/VM 7.3.0) [ 112.690568] Call Trace: [ 112.690571] [<000003ffe0eb77fe>] dump_stack_lvl+0x76/0xa0 [ 112.690579] [<000003ffe03f4a90>] print_bad_pte+0x280/0x2d0 [ 112.690584] [<000003ffe03f7654>] zap_present_ptes.isra.0+0x5c4/0x870 [ 112.690598] [<000003ffe03f7a46>] zap_pte_range+0x146/0x3d0 [ 112.690601] [<000003ffe03f7f1c>] zap_p4d_range+0x24c/0x4b0 [ 112.690603] [<000003ffe03f84ea>] unmap_page_range+0xea/0x2c0 [ 112.690605] [<000003ffe03f8754>] unmap_single_vma.isra.0+0x94/0xf0 [ 112.690607] [<000003ffe03f8866>] unmap_vmas+0xb6/0x1a0 [ 112.690609] [<000003ffe0405724>] exit_mmap+0xc4/0x3e0 [ 112.690613] [<000003ffe0154aa2>] mmput+0x72/0x170 [ 112.690616] [<000003ffe015e2c6>] exit_mm+0xd6/0x150 [ 112.690618] [<000003ffe015e52c>] do_exit+0x1ec/0x490 [ 112.690620] [<000003ffe015e9a4>] do_group_exit+0x44/0xc0 [ 112.690621] [<000003ffe016f000>] get_signal+0x7f0/0x800 [ 112.690624] [<000003ffe0108614>] arch_do_signal_or_restart+0x74/0x320 [ 112.690628] [<000003ffe020c876>] syscall_exit_to_user_mode_work+0xe6/0x170 [ 112.690632] [<000003ffe0eb7c04>] __do_syscall+0xd4/0x1c0 [ 112.690634] [<000003ffe0ec303c>] system_call+0x74/0x98 [ 112.690638] Disabling lock debugging due to kernel taint To reproduce, running the ksm01 testsuite from ltp seems to be enough. The splat is always triggered immediately. The output from ksm01 is: tst_kconfig.c:88: TINFO: Parsing kernel config '/proc/config.gz' tst_test.c:1809: TINFO: LTP version: 20240524-208-g6c3293c6f tst_test.c:1813: TINFO: Tested kernel: 6.11.0-rc5-next-20240827 #1440 SMP Thu Aug 29 12:13:28 CEST 2024 s390x tst_test.c:1652: TINFO: Timeout per run is 0h 00m 30s mem.c:422: TINFO: wait for all children to stop. mem.c:388: TINFO: child 0 stops. mem.c:388: TINFO: child 1 stops. mem.c:388: TINFO: child 2 stops. mem.c:495: TINFO: KSM merging... mem.c:434: TINFO: resume all children. mem.c:422: TINFO: wait for all children to stop. mem.c:344: TINFO: child 0 continues... mem.c:347: TINFO: child 0 allocates 128 MB filled with 'c' mem.c:344: TINFO: child 1 continues... mem.c:347: TINFO: child 1 allocates 128 MB filled with 'a' mem.c:344: TINFO: child 2 continues... mem.c:347: TINFO: child 2 allocates 128 MB filled with 'a' mem.c:400: TINFO: child 1 stops. mem.c:400: TINFO: child 2 stops. mem.c:400: TINFO: child 0 stops. Test timeouted, sending SIGKILL! tst_test.c:1700: TINFO: Killed the leftover descendant processes tst_test.c:1706: TINFO: If you are running on slow machine, try exporting LTP_TIMEOUT_MUL > 1 tst_test.c:1708: TBROK: Test killed! (timeout?) Thanks Sven
