On Fri, Dec 12, 2025 at 3:30 AM Ming Lei <[email protected]> wrote: > > On Thu, Dec 11, 2025 at 09:21:37PM -0800, Caleb Sander Mateos wrote: > > On Thu, Dec 11, 2025 at 9:14 PM Ming Lei <[email protected]> wrote: > > > > > > On Thu, Dec 11, 2025 at 08:59:00PM -0800, Caleb Sander Mateos wrote: > > > > On Thu, Dec 11, 2025 at 6:38 PM Ming Lei <[email protected]> wrote: > > > > > > > > > > On Thu, Dec 11, 2025 at 06:06:51PM -0800, Caleb Sander Mateos wrote: > > > > > > On Thu, Dec 11, 2025 at 3:05 PM Ming Lei <[email protected]> > > > > > > wrote: > > > > > > > > > > > > > > On Thu, Dec 11, 2025 at 10:45:36AM -0800, Caleb Sander Mateos > > > > > > > wrote: > > > > > > > > On Thu, Dec 11, 2025 at 1:09 AM Ming Lei <[email protected]> > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > On Wed, Dec 10, 2025 at 10:16:01PM -0700, Caleb Sander Mateos > > > > > > > > > wrote: > > > > > > > > > > The kublk mock ublk server allows multiple data copy mode > > > > > > > > > > arguments to > > > > > > > > > > be passed on the command line (--zero_copy, --get_data, and > > > > > > > > > > --auto_zc). > > > > > > > > > > The ublk device will be created with all the requested > > > > > > > > > > feature flags, > > > > > > > > > > however kublk will only use one of the modes to interact > > > > > > > > > > with request > > > > > > > > > > data (arbitrarily preferring auto_zc over zero_copy over > > > > > > > > > > get_data). To > > > > > > > > > > clarify the intent of the test, don't allow multiple data > > > > > > > > > > copy modes to > > > > > > > > > > be specified. Don't set UBLK_F_USER_COPY for zero_copy, as > > > > > > > > > > it's an > > > > > > > > > > independent feature. Don't require zero_copy for > > > > > > > > > > auto_zc_fallback, as > > > > > > > > > > only auto_zc is needed. Fix the test cases passing multiple > > > > > > > > > > data copy > > > > > > > > > > mode arguments. > > > > > > > > > > > > > > > > > > > > Signed-off-by: Caleb Sander Mateos <[email protected]> > > > > > > > > > > --- > > > > > > > > > > tools/testing/selftests/ublk/kublk.c | 21 > > > > > > > > > > ++++++++++++------- > > > > > > > > > > .../testing/selftests/ublk/test_generic_09.sh | 2 +- > > > > > > > > > > .../testing/selftests/ublk/test_stress_03.sh | 4 ++-- > > > > > > > > > > .../testing/selftests/ublk/test_stress_04.sh | 2 +- > > > > > > > > > > .../testing/selftests/ublk/test_stress_05.sh | 10 > > > > > > > > > > ++++----- > > > > > > > > > > 5 files changed, 22 insertions(+), 17 deletions(-) > > > > > > > > > > > > > > > > > > > > diff --git a/tools/testing/selftests/ublk/kublk.c > > > > > > > > > > b/tools/testing/selftests/ublk/kublk.c > > > > > > > > > > index f8fa102a627f..1765c4806523 100644 > > > > > > > > > > --- a/tools/testing/selftests/ublk/kublk.c > > > > > > > > > > +++ b/tools/testing/selftests/ublk/kublk.c > > > > > > > > > > @@ -1611,11 +1611,11 @@ int main(int argc, char *argv[]) > > > > > > > > > > break; > > > > > > > > > > case 'd': > > > > > > > > > > ctx.queue_depth = strtol(optarg, > > > > > > > > > > NULL, 10); > > > > > > > > > > break; > > > > > > > > > > case 'z': > > > > > > > > > > - ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY > > > > > > > > > > | UBLK_F_USER_COPY; > > > > > > > > > > + ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY; > > > > > > > > > > break; > > > > > > > > > > case 'r': > > > > > > > > > > value = strtol(optarg, NULL, 10); > > > > > > > > > > if (value) > > > > > > > > > > ctx.flags |= > > > > > > > > > > UBLK_F_USER_RECOVERY; > > > > > > > > > > @@ -1674,17 +1674,22 @@ int main(int argc, char *argv[]) > > > > > > > > > > optind += 1; > > > > > > > > > > break; > > > > > > > > > > } > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > - /* auto_zc_fallback depends on F_AUTO_BUF_REG & > > > > > > > > > > F_SUPPORT_ZERO_COPY */ > > > > > > > > > > - if (ctx.auto_zc_fallback && > > > > > > > > > > - !((ctx.flags & UBLK_F_AUTO_BUF_REG) && > > > > > > > > > > - (ctx.flags & UBLK_F_SUPPORT_ZERO_COPY))) { > > > > > > > > > > - ublk_err("%s: auto_zc_fallback is set but > > > > > > > > > > neither " > > > > > > > > > > - "F_AUTO_BUF_REG nor > > > > > > > > > > F_SUPPORT_ZERO_COPY is enabled\n", > > > > > > > > > > - __func__); > > > > > > > > > > + /* auto_zc_fallback depends on F_AUTO_BUF_REG */ > > > > > > > > > > + if (ctx.auto_zc_fallback && !(ctx.flags & > > > > > > > > > > UBLK_F_AUTO_BUF_REG)) { > > > > > > > > > > + ublk_err("%s: auto_zc_fallback is set but > > > > > > > > > > F_AUTO_BUF_REG is disabled\n", > > > > > > > > > > + __func__); > > > > > > > > > > + return -EINVAL; > > > > > > > > > > + } > > > > > > > > > > + > > > > > > > > > > + if (!!(ctx.flags & UBLK_F_SUPPORT_ZERO_COPY) + > > > > > > > > > > + !!(ctx.flags & UBLK_F_NEED_GET_DATA) + > > > > > > > > > > + !!(ctx.flags & UBLK_F_USER_COPY) + > > > > > > > > > > + !!(ctx.flags & UBLK_F_AUTO_BUF_REG) > 1) { > > > > > > > > > > + fprintf(stderr, "too many data copy modes > > > > > > > > > > specified\n"); > > > > > > > > > > return -EINVAL; > > > > > > > > > > } > > > > > > > > > > > > > > > > > > Actually most of them are allowed to co-exist, such as > > > > > > > > > -z/--auto_zc/-u. > > > > > > > > > > > > > > > > Yes, I know the ublk driver allows multiple copy mode flags to > > > > > > > > be set > > > > > > > > (though it will clear UBLK_F_NEED_GET_DATA if any of the others > > > > > > > > are > > > > > > > > set). However, kublk will only actually use one of the modes. > > > > > > > > For > > > > > > > > example, --get_data --zero_copy will use zero copy for the data > > > > > > > > transfer, not get data. And --zero_copy --auto_zc will only use > > > > > > > > auto > > > > > > > > buffer registration. So I think it's confusing to allow > > > > > > > > multiple of > > > > > > > > these parameters to be passed to kublk. Or do you think there > > > > > > > > is value > > > > > > > > in testing ublk device creation with multiple data copy mode > > > > > > > > flags > > > > > > > > set, but only one of the modes actually used? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > i = optind; > > > > > > > > > > while (i < argc && ctx.nr_files < MAX_BACK_FILES) { > > > > > > > > > > diff --git > > > > > > > > > > a/tools/testing/selftests/ublk/test_generic_09.sh > > > > > > > > > > b/tools/testing/selftests/ublk/test_generic_09.sh > > > > > > > > > > index bb6f77ca5522..145e17b3d2b0 100755 > > > > > > > > > > --- a/tools/testing/selftests/ublk/test_generic_09.sh > > > > > > > > > > +++ b/tools/testing/selftests/ublk/test_generic_09.sh > > > > > > > > > > @@ -14,11 +14,11 @@ if ! _have_program fio; then > > > > > > > > > > exit "$UBLK_SKIP_CODE" > > > > > > > > > > fi > > > > > > > > > > > > > > > > > > > > _prep_test "null" "basic IO test" > > > > > > > > > > > > > > > > > > > > -dev_id=$(_add_ublk_dev -t null -z --auto_zc > > > > > > > > > > --auto_zc_fallback) > > > > > > > > > > +dev_id=$(_add_ublk_dev -t null --auto_zc > > > > > > > > > > --auto_zc_fallback) > > > > > > > > > > _check_add_dev $TID $? > > > > > > > > > > > > > > > > > > > > # run fio over the two disks > > > > > > > > > > fio --name=job1 --filename=/dev/ublkb"${dev_id}" > > > > > > > > > > --ioengine=libaio --rw=readwrite --iodepth=32 --size=256M > > > > > > > > > > > /dev/null 2>&1 > > > > > > > > > > ERR_CODE=$? > > > > > > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_03.sh > > > > > > > > > > b/tools/testing/selftests/ublk/test_stress_03.sh > > > > > > > > > > index 3ed4c9b2d8c0..8e9f2786ef9c 100755 > > > > > > > > > > --- a/tools/testing/selftests/ublk/test_stress_03.sh > > > > > > > > > > +++ b/tools/testing/selftests/ublk/test_stress_03.sh > > > > > > > > > > @@ -36,19 +36,19 @@ wait > > > > > > > > > > > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > > > > > > ublk_io_and_remove 8G -t null -q 4 --auto_zc & > > > > > > > > > > ublk_io_and_remove 256M -t loop -q 4 --auto_zc > > > > > > > > > > "${UBLK_BACKFILES[0]}" & > > > > > > > > > > ublk_io_and_remove 256M -t stripe -q 4 --auto_zc > > > > > > > > > > "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" & > > > > > > > > > > - ublk_io_and_remove 8G -t null -q 4 -z --auto_zc > > > > > > > > > > --auto_zc_fallback & > > > > > > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc > > > > > > > > > > --auto_zc_fallback & > > > > > > > > > > wait > > > > > > > > > > fi > > > > > > > > > > > > > > > > > > > > if _have_feature "PER_IO_DAEMON"; then > > > > > > > > > > ublk_io_and_remove 8G -t null -q 4 --auto_zc > > > > > > > > > > --nthreads 8 --per_io_tasks & > > > > > > > > > > ublk_io_and_remove 256M -t loop -q 4 --auto_zc > > > > > > > > > > --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[0]}" & > > > > > > > > > > ublk_io_and_remove 256M -t stripe -q 4 --auto_zc > > > > > > > > > > --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[1]}" > > > > > > > > > > "${UBLK_BACKFILES[2]}" & > > > > > > > > > > - ublk_io_and_remove 8G -t null -q 4 -z --auto_zc > > > > > > > > > > --auto_zc_fallback --nthreads 8 --per_io_tasks & > > > > > > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc > > > > > > > > > > --auto_zc_fallback --nthreads 8 --per_io_tasks & > > > > > > > > > > wait > > > > > > > > > > fi > > > > > > > > > > > > > > > > > > > > _cleanup_test "stress" > > > > > > > > > > _show_result $TID $ERR_CODE > > > > > > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_04.sh > > > > > > > > > > b/tools/testing/selftests/ublk/test_stress_04.sh > > > > > > > > > > index c7220723b537..6e165a1f90b4 100755 > > > > > > > > > > --- a/tools/testing/selftests/ublk/test_stress_04.sh > > > > > > > > > > +++ b/tools/testing/selftests/ublk/test_stress_04.sh > > > > > > > > > > @@ -35,11 +35,11 @@ wait > > > > > > > > > > > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > > > > > > ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc & > > > > > > > > > > ublk_io_and_kill_daemon 256M -t loop -q 4 --auto_zc > > > > > > > > > > "${UBLK_BACKFILES[0]}" & > > > > > > > > > > ublk_io_and_kill_daemon 256M -t stripe -q 4 --auto_zc > > > > > > > > > > --no_ublk_fixed_fd "${UBLK_BACKFILES[1]}" > > > > > > > > > > "${UBLK_BACKFILES[2]}" & > > > > > > > > > > - ublk_io_and_kill_daemon 8G -t null -q 4 -z --auto_zc > > > > > > > > > > --auto_zc_fallback & > > > > > > > > > > + ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc > > > > > > > > > > --auto_zc_fallback & > > > > > > > > > > wait > > > > > > > > > > fi > > > > > > > > > > > > > > > > > > > > if _have_feature "PER_IO_DAEMON"; then > > > > > > > > > > ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc > > > > > > > > > > --nthreads 8 --per_io_tasks & > > > > > > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_05.sh > > > > > > > > > > b/tools/testing/selftests/ublk/test_stress_05.sh > > > > > > > > > > index 274295061042..09b94c36f2ba 100755 > > > > > > > > > > --- a/tools/testing/selftests/ublk/test_stress_05.sh > > > > > > > > > > +++ b/tools/testing/selftests/ublk/test_stress_05.sh > > > > > > > > > > @@ -56,21 +56,21 @@ for reissue in $(seq 0 1); do > > > > > > > > > > wait > > > > > > > > > > done > > > > > > > > > > > > > > > > > > > > if _have_feature "ZERO_COPY"; then > > > > > > > > > > for reissue in $(seq 0 1); do > > > > > > > > > > - ublk_io_and_remove 8G -t null -q 4 -g -z -r 1 > > > > > > > > > > -i "$reissue" & > > > > > > > > > > - ublk_io_and_remove 256M -t loop -q 4 -g -z -r > > > > > > > > > > 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > > > > > > + ublk_io_and_remove 8G -t null -q 4 -z -r 1 -i > > > > > > > > > > "$reissue" & > > > > > > > > > > + ublk_io_and_remove 256M -t loop -q 4 -z -r 1 > > > > > > > > > > -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > > > > > > wait > > > > > > > > > > done > > > > > > > > > > fi > > > > > > > > > > > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > > > > > > for reissue in $(seq 0 1); do > > > > > > > > > > - ublk_io_and_remove 8G -t null -q 4 -g > > > > > > > > > > --auto_zc -r 1 -i "$reissue" & > > > > > > > > > > - ublk_io_and_remove 256M -t loop -q 4 -g > > > > > > > > > > --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > > > > > > - ublk_io_and_remove 8G -t null -q 4 -g -z > > > > > > > > > > --auto_zc --auto_zc_fallback -r 1 -i "$reissue" & > > > > > > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc > > > > > > > > > > -r 1 -i "$reissue" & > > > > > > > > > > + ublk_io_and_remove 256M -t loop -q 4 > > > > > > > > > > --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc > > > > > > > > > > --auto_zc_fallback -r 1 -i "$reissue" & > > > > > > > > > > > > > > > > > > --auto_zc_fallback requires both -z and --auto_zc. > > > > > > > > > > > > > > > > Ah, right, I forgot that the fallback path relies on normal > > > > > > > > zero copy > > > > > > > > buffer registration. I guess we are missing coverage of that, > > > > > > > > then, > > > > > > > > since the tests still passed with --zero_copy disabled. > > > > > > > > > > > > > > Looks one regression from commit 0a9beafa7c63 ("ublk: refactor > > > > > > > auto buffer register in ublk_dispatch_req()") > > > > > > > > > > > > Is there a particular issue you see in that commit? I think the > > > > > > issue > > > > > > > > > > Looks I overlooked. > > > > > > > > > > > is that if UBLK_IO_F_NEED_REG_BUF is set in the ublksrv_io_desc but > > > > > > zc > > > > > > isn't enabled, the null ublk server will just complete the I/O > > > > > > immediately. And --auto_zc_fallback isn't supported by any of the > > > > > > other ublk servers. > > > > > > > > > > > > if (auto_zc && !ublk_io_auto_zc_fallback(iod)) > > > > > > queued = null_queue_auto_zc_io(t, q, tag); > > > > > > else if (zc) > > > > > > queued = null_queue_zc_io(t, q, tag); > > > > > > else { > > > > > > ublk_complete_io(t, q, tag, iod->nr_sectors << 9); > > > > > > return 0; > > > > > > } > > > > > > > > > > > > So it looks to me to just be an issue with my kublk change. > > > > > > > > > > But ublk_queue_auto_zc_fallback() is broken, so the auto_zc_fallback > > > > > code > > > > > path isn't examined actually. > > > > > > > > How is it broken? > > > > > > typeof(q->flags) is u64, but the return type is i32, so it is overflowed. > > > > Ah, good catch. Yeah, these ublk_queue flag query functions should > > probably return bool. Are you going to send out a patch? > > I guess you may have to send V3 for fixing patch 4, I appreciate you may > include the > following fix in your V3, otherwise it may conflict with the added > ublk_queue_use_user_copy().
Sure, will do. Thanks, Caleb > > > From 62da81c7a9883dc251cc0daa2a3081226abc5da1 Mon Sep 17 00:00:00 2001 > From: Ming Lei <[email protected]> > Date: Fri, 12 Dec 2025 11:23:56 +0000 > Subject: [PATCH] selftests: ublk: fix overflow in > ublk_queue_auto_zc_fallback() > > The functions ublk_queue_use_zc(), ublk_queue_use_auto_zc(), and > ublk_queue_auto_zc_fallback() were returning int, but performing > bitwise AND on q->flags which is __u64. > > When a flag bit is set in the upper 32 bits (beyond INT_MAX), the > result of the bitwise AND operation could overflow when cast to int, > leading to incorrect boolean evaluation. > > For example, if UBLKS_Q_AUTO_BUF_REG_FALLBACK is 0x8000000000000000: > - (u64)flags & 0x8000000000000000 = 0x8000000000000000 > - Cast to int: undefined behavior / incorrect value > - Used in if(): may evaluate incorrectly > > Fix by: > 1. Changing return type from int to bool for semantic correctness > 2. Using !! to explicitly convert to boolean (0 or 1) > > This ensures the functions return proper boolean values regardless > of which bit position the flags occupy in the 64-bit field. > > Fixes: c3a6d48f86da ("selftests: ublk: remove ublk queue self-defined flags") > Signed-off-by: Ming Lei <[email protected]> > --- > tools/testing/selftests/ublk/kublk.h | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/tools/testing/selftests/ublk/kublk.h > b/tools/testing/selftests/ublk/kublk.h > index fda72e19ef09..8a83b90ec603 100644 > --- a/tools/testing/selftests/ublk/kublk.h > +++ b/tools/testing/selftests/ublk/kublk.h > @@ -396,19 +396,19 @@ static inline int ublk_completed_tgt_io(struct > ublk_thread *t, > return --io->tgt_ios == 0; > } > > -static inline int ublk_queue_use_zc(const struct ublk_queue *q) > +static inline bool ublk_queue_use_zc(const struct ublk_queue *q) > { > - return q->flags & UBLK_F_SUPPORT_ZERO_COPY; > + return !!(q->flags & UBLK_F_SUPPORT_ZERO_COPY); > } > > -static inline int ublk_queue_use_auto_zc(const struct ublk_queue *q) > +static inline bool ublk_queue_use_auto_zc(const struct ublk_queue *q) > { > - return q->flags & UBLK_F_AUTO_BUF_REG; > + return !!(q->flags & UBLK_F_AUTO_BUF_REG); > } > > -static inline int ublk_queue_auto_zc_fallback(const struct ublk_queue *q) > +static inline bool ublk_queue_auto_zc_fallback(const struct ublk_queue *q) > { > - return q->flags & UBLKS_Q_AUTO_BUF_REG_FALLBACK; > + return !!(q->flags & UBLKS_Q_AUTO_BUF_REG_FALLBACK); > } > > static inline bool ublk_queue_use_user_copy(const struct ublk_queue *q) > -- > 2.47.1 > > > > > Thanks, > Ming >
