From d64ebe7eb7df8c622b20bca38f3d7f4c7bb033c9 Mon Sep 17 00:00:00 2001 From: "zhengbing.huang" Date: Sun, 15 Dec 2024 14:50:56 +0800 Subject: [PATCH] drbd: Fix memory leak In the output of kmemleak, we have the followe backtrace: unreferenced object 0xffff8885b57cda80 (size 64): comm "drbd_r_testimg4", pid 37104, jiffies 4494192827 (age 127162.843s) hex dump (first 32 bytes): 31 20 6f 66 20 32 20 6e 6f 64 65 73 20 76 69 73 1 of 2 nodes vis 69 62 6c 65 2c 20 6e 65 65 64 20 32 20 66 6f 72 ible, need 2 for backtrace: [<000000006d641d68>] __kmalloc_track_caller+0x15c/0x270 [<000000006a7ffbcf>] kvasprintf+0xa7/0x120 [<000000002d2f15b3>] drbd_state_err+0xa9/0x190 [drbd] [<000000006aa2f3df>] __is_valid_soft_transition+0xe99/0xec0 [drbd] [<0000000009d68cc7>] try_state_change+0x4f0/0x840 [drbd] [<00000000d5640f06>] ___end_state_change+0x140/0x12a0 [drbd] [<000000009f4b8d71>] __end_state_change+0xa1/0x130 [drbd] [<000000001c6de1a7>] change_connection_state+0x5ee/0xbd0 [drbd] [<00000000ce4408d6>] process_twopc+0x1d3e/0x2ce0 [drbd] [<00000000df3af6e8>] receive_twopc+0x17b/0x2b0 [drbd] [<000000009701f919>] drbd_receiver+0x311/0x6e0 [drbd] [<0000000092c4aeb1>] drbd_thread_setup+0x19d/0x430 [drbd] [<0000000098e316ab>] kthread+0x19c/0x1c0 [<000000004c72b3a8>] ret_from_fork+0x1f/0x40 This is a memory leak. In drbd_state_err() function, if resource->state_change_err_str is a null pointer, the err_str will not be free. And _drbd_state_err() has same issues. So, if err_str has not put to up layer, free it in current function. Signed-off-by: zhengbing.huang Signed-off-by: Joel Colledge --- drbd/drbd_state.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drbd/drbd_state.c b/drbd/drbd_state.c index f498eaa60396..0e693c8e3af0 100644 --- a/drbd/drbd_state.c +++ b/drbd/drbd_state.c @@ -1557,10 +1557,13 @@ static __printf(2, 3) void _drbd_state_err(struct change_context *context, const va_end(args); if (!err_str) return; - if (context->err_str) - *context->err_str = err_str; if (context->flags & CS_VERBOSE) drbd_err(resource, "%s\n", err_str); + + if (context->err_str) + *context->err_str = err_str; + else + kfree(err_str); } static __printf(2, 3) void drbd_state_err(struct drbd_resource *resource, const char *fmt, ...) @@ -1573,10 +1576,13 @@ static __printf(2, 3) void drbd_state_err(struct drbd_resource *resource, const va_end(args); if (!err_str) return; - if (resource->state_change_err_str) - *resource->state_change_err_str = err_str; if (resource->state_change_flags & CS_VERBOSE) drbd_err(resource, "%s\n", err_str); + + if (resource->state_change_err_str) + *resource->state_change_err_str = err_str; + else + kfree(err_str); } static enum drbd_state_rv __is_valid_soft_transition(struct drbd_resource *resource) -- 2.43.0