The patch titled Subject: kmemleak: drop (age <increasing>) from leak record has been added to the -mm mm-unstable branch. Its filename is kmemleak-drop-age-increasing-from-leak-record.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kmemleak-drop-age-increasing-from-leak-record.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Jim Cromie <jim.cromie@xxxxxxxxx> Subject: kmemleak: drop (age <increasing>) from leak record Date: Thu, 16 Nov 2023 15:43:17 -0700 Patch series "tweak kmemleak report format". These 2 patches make minor changes to the report: 1st strips "age <increasing>" from output. This makes the output idempotent; unchanging until a new leak is reported. 2nd adds the backtrace.checksum to the "backtrace:" line. This lets a user see repeats without actually reading the whole backtrace. So now the backtrace line looks like this: backtrace (crc 603070071): I surveyed for un-wanted effects upon users: Syzkaller parses kmemleak in executor/common_linux.h: static void check_leaks(char** frames, int nframes) It just counts occurrences of "unreferenced object", specifically it does not look for "age", nor would it choke on "crc" being added. github has 3 repos with "kmemleak" mentioned, all are moribund. gitlab has 0 hits on "kmemleak". This patch (of 2): Displaying age is pretty, but counter-productive; it changes with current-time, so it surrenders idempotency of the output, which breaks simple hash-based cataloging of the records by the user. The trouble: sequential reads, wo new leaks, get new results: :#> sum /sys/kernel/debug/kmemleak 53439 74 /sys/kernel/debug/kmemleak :#> sum /sys/kernel/debug/kmemleak 59066 74 /sys/kernel/debug/kmemleak and age is why (nothing else changes): :#> grep -v age /sys/kernel/debug/kmemleak | sum 58894 67 :#> grep -v age /sys/kernel/debug/kmemleak | sum 58894 67 Since jiffies is already printed in the "comm" line, age adds nothing. Notably, syzkaller reads kmemleak only for "unreferenced object", and won't care about this reform of age-ism. A few moribund github repos mention it, but don't compile. Link: https://lkml.kernel.org/r/20231116224318.124209-1-jim.cromie@xxxxxxxxx Link: https://lkml.kernel.org/r/20231116224318.124209-2-jim.cromie@xxxxxxxxx Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/kmemleak.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/mm/kmemleak.c~kmemleak-drop-age-increasing-from-leak-record +++ a/mm/kmemleak.c @@ -355,14 +355,12 @@ static void print_unreferenced(struct se int i; unsigned long *entries; unsigned int nr_entries; - unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); nr_entries = stack_depot_fetch(object->trace_handle, &entries); warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", object->pointer, object->size); - warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", - object->comm, object->pid, object->jiffies, - msecs_age / 1000, msecs_age % 1000); + warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", + object->comm, object->pid, object->jiffies); hex_dump_object(seq, object); warn_or_seq_printf(seq, " backtrace:\n"); _ Patches currently in -mm which might be from jim.cromie@xxxxxxxxx are kmemleak-drop-age-increasing-from-leak-record.patch kmemleak-add-checksum-to-backtrace-report.patch