diff options
| author | Honggyu Kim <honggyu.kim@sk.com> | 2025-07-02 09:02:01 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-09 21:07:54 -0700 |
| commit | d9e01c62b7a0c258a7481c083f84c766a8f5597c (patch) | |
| tree | 3312a8c0fc31407c6da54f50e5fc304c2a8df420 | |
| parent | 6ee9b3d84775944fb8c8a447961cd01274ac671c (diff) | |
samples/damon: fix damon sample prcl for start failure
Patch series "mm/damon: fix divide by zero and its samples", v3.
This series includes fixes against damon and its samples to make it safer
when damon sample starting fails.
It includes the following changes.
- fix unexpected divide by zero crash for zero size regions
- fix bugs for damon samples in case of start failures
This patch (of 4):
The damon_sample_prcl_start() can fail so we must reset the "enable"
parameter to "false" again for proper rollback.
In such cases, setting Y to "enable" then N triggers the following crash
because damon sample start failed but the "enable" stays as Y.
[ 2441.419649] damon_sample_prcl: start
[ 2454.146817] damon_sample_prcl: stop
[ 2454.146862] ------------[ cut here ]------------
[ 2454.146865] kernel BUG at mm/slub.c:546!
[ 2454.148183] Oops: invalid opcode: 0000 [#1] SMP NOPTI
...
[ 2454.167555] Call Trace:
[ 2454.167822] <TASK>
[ 2454.168061] damon_destroy_ctx+0x78/0x140
[ 2454.168454] damon_sample_prcl_enable_store+0x8d/0xd0
[ 2454.168932] param_attr_store+0xa1/0x120
[ 2454.169315] module_attr_store+0x20/0x50
[ 2454.169695] sysfs_kf_write+0x72/0x90
[ 2454.170065] kernfs_fop_write_iter+0x150/0x1e0
[ 2454.170491] vfs_write+0x315/0x440
[ 2454.170833] ksys_write+0x69/0xf0
[ 2454.171162] __x64_sys_write+0x19/0x30
[ 2454.171525] x64_sys_call+0x18b2/0x2700
[ 2454.171900] do_syscall_64+0x7f/0x680
[ 2454.172258] ? exit_to_user_mode_loop+0xf6/0x180
[ 2454.172694] ? clear_bhb_loop+0x30/0x80
[ 2454.173067] ? clear_bhb_loop+0x30/0x80
[ 2454.173439] entry_SYSCALL_64_after_hwframe+0x76/0x7e
Link: https://lkml.kernel.org/r/20250702000205.1921-1-honggyu.kim@sk.com
Link: https://lkml.kernel.org/r/20250702000205.1921-2-honggyu.kim@sk.com
Fixes: 2aca254620a8 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | samples/damon/prcl.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/samples/damon/prcl.c b/samples/damon/prcl.c index 056b1b21a0fe..5597e6a08ab2 100644 --- a/samples/damon/prcl.c +++ b/samples/damon/prcl.c @@ -122,8 +122,12 @@ static int damon_sample_prcl_enable_store( if (enable == enabled) return 0; - if (enable) - return damon_sample_prcl_start(); + if (enable) { + err = damon_sample_prcl_start(); + if (err) + enable = false; + return err; + } damon_sample_prcl_stop(); return 0; } |