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Hi @CZom!

Thanks for your contribution to the Linux kernel!

Linux kernel development happens on mailing lists, rather than on GitHub - this GitHub repository is a read-only mirror that isn't used for accepting contributions. So that your change can become part of Linux, please email it to us as a patch.

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Further information

Happy hacking!

This message was posted by a bot - if you have any questions or suggestions, please talk to my owners, @ajdlinux and @daxtens, or raise an issue at https://github.com/ajdlinux/KernelPRBot.

@compdzwio compdzwio closed this Apr 23, 2018
cdleonard pushed a commit to cdleonard/linux that referenced this pull request May 8, 2019
Typedef is not recommended in the Linux kernel.The klocwork static code
analyzer takes the enumeration as the full range of intel_gvt_gtt_type_t.
But the intel_gvt_gtt_type_t will never be used in full range. For
example, the GTT_TYPE_INVALID will never be used as an index of an array.
Remove the typedef and let the enumeration starts from zero to pass
klocwork analysis.

This patch fixed the critial issues torvalds#483, torvalds#551, torvalds#665 reported by
klockwork.

v3:
- Remove the typedef and let the enumeration starts from zero.

Signed-off-by: Aleksei Gimbitskii <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
CC: Colin Xu <[email protected]>
Reviewed-by: Colin Xu <[email protected]>
Signed-off-by: Zhenyu Wang <[email protected]>
fengguang pushed a commit to 0day-ci/linux that referenced this pull request Mar 15, 2021
This commit fixes the following checkpatch.pl errors:

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#535: FILE: ./hal/HalBtcOutSrc.h:535:
    +void EXhalbtcoutsrc_PowerOnSetting(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#536: FILE: ./hal/HalBtcOutSrc.h:536:
    +void EXhalbtcoutsrc_InitHwConfig(struct BTC_COEXIST * pBtCoexist, u8 bWifiOnly);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#537: FILE: ./hal/HalBtcOutSrc.h:537:
    +void EXhalbtcoutsrc_InitCoexDm(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#538: FILE: ./hal/HalBtcOutSrc.h:538:
    +void EXhalbtcoutsrc_IpsNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#539: FILE: ./hal/HalBtcOutSrc.h:539:
    +void EXhalbtcoutsrc_LpsNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#540: FILE: ./hal/HalBtcOutSrc.h:540:
    +void EXhalbtcoutsrc_ScanNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#541: FILE: ./hal/HalBtcOutSrc.h:541:
    +void EXhalbtcoutsrc_ConnectNotify(struct BTC_COEXIST * pBtCoexist, u8 action);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#543: FILE: ./hal/HalBtcOutSrc.h:543:
    +	struct BTC_COEXIST * pBtCoexist, enum RT_MEDIA_STATUS mediaStatus

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#545: FILE: ./hal/HalBtcOutSrc.h:545:
    +void EXhalbtcoutsrc_SpecialPacketNotify(struct BTC_COEXIST * pBtCoexist, u8 pktType);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#547: FILE: ./hal/HalBtcOutSrc.h:547:
    +	struct BTC_COEXIST * pBtCoexist, u8 *tmpBuf, u8 length

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#549: FILE: ./hal/HalBtcOutSrc.h:549:
    +void EXhalbtcoutsrc_HaltNotify(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#550: FILE: ./hal/HalBtcOutSrc.h:550:
    +void EXhalbtcoutsrc_PnpNotify(struct BTC_COEXIST * pBtCoexist, u8 pnpState);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#551: FILE: ./hal/HalBtcOutSrc.h:551:
    +void EXhalbtcoutsrc_Periodical(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#555: FILE: ./hal/HalBtcOutSrc.h:555:
    +void EXhalbtcoutsrc_DisplayBtCoexInfo(struct BTC_COEXIST * pBtCoexist);

Signed-off-by: Marco Cesati <[email protected]>
fengguang pushed a commit to 0day-ci/linux that referenced this pull request Mar 15, 2021
This commit fixes the following checkpatch.pl errors:

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#57: FILE: ./hal/HalPhyRf_8723B.c:57:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#138: FILE: ./hal/HalPhyRf_8723B.c:138:
    +static void setCCKFilterCoefficient(struct DM_ODM_T * pDM_Odm, u8 CCKSwingIndex)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#162: FILE: ./hal/HalPhyRf_8723B.c:162:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#188: FILE: ./hal/HalPhyRf_8723B.c:188:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#363: FILE: ./hal/HalPhyRf_8723B.c:363:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#371: FILE: ./hal/HalPhyRf_8723B.c:371:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#412: FILE: ./hal/HalPhyRf_8723B.c:412:
    +void ConfigureTxpowerTrack_8723B(struct TXPWRTRACK_CFG * pConfig)

    ERROR:POINTER_LOCATION: "foo *		bar" should be "foo *bar"
    torvalds#440: FILE: ./hal/HalPhyRf_8723B.c:440:
    +	struct DM_ODM_T *		pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#551: FILE: ./hal/HalPhyRf_8723B.c:551:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#765: FILE: ./hal/HalPhyRf_8723B.c:765:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#872: FILE: ./hal/HalPhyRf_8723B.c:872:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1095: FILE: ./hal/HalPhyRf_8723B.c:1095:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1097: FILE: ./hal/HalPhyRf_8723B.c:1097:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1175: FILE: ./hal/HalPhyRf_8723B.c:1175:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1177: FILE: ./hal/HalPhyRf_8723B.c:1177:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1250: FILE: ./hal/HalPhyRf_8723B.c:1250:
    +void ODM_SetIQCbyRFpath(struct DM_ODM_T * pDM_Odm, u32 RFpath)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1253: FILE: ./hal/HalPhyRf_8723B.c:1253:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1295: FILE: ./hal/HalPhyRf_8723B.c:1295:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo *		bar" should be "foo *bar"
    torvalds#1313: FILE: ./hal/HalPhyRf_8723B.c:1313:
    +	struct DM_ODM_T *		pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1333: FILE: ./hal/HalPhyRf_8723B.c:1333:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1363: FILE: ./hal/HalPhyRf_8723B.c:1363:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1387: FILE: ./hal/HalPhyRf_8723B.c:1387:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1492: FILE: ./hal/HalPhyRf_8723B.c:1492:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1700: FILE: ./hal/HalPhyRf_8723B.c:1700:
    +static void phy_LCCalibrate_8723B(struct DM_ODM_T * pDM_Odm, bool is2T)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1787: FILE: ./hal/HalPhyRf_8723B.c:1787:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1833: FILE: ./hal/HalPhyRf_8723B.c:1833:
    +		struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #2041: FILE: ./hal/HalPhyRf_8723B.c:2041:
    +void PHY_LCCalibrate_8723B(struct DM_ODM_T * pDM_Odm)

Signed-off-by: Marco Cesati <[email protected]>
fengguang pushed a commit to 0day-ci/linux that referenced this pull request Mar 16, 2021
This commit fixes the following checkpatch.pl errors:

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#535: FILE: ./hal/HalBtcOutSrc.h:535:
    +void EXhalbtcoutsrc_PowerOnSetting(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#536: FILE: ./hal/HalBtcOutSrc.h:536:
    +void EXhalbtcoutsrc_InitHwConfig(struct BTC_COEXIST * pBtCoexist, u8 bWifiOnly);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#537: FILE: ./hal/HalBtcOutSrc.h:537:
    +void EXhalbtcoutsrc_InitCoexDm(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#538: FILE: ./hal/HalBtcOutSrc.h:538:
    +void EXhalbtcoutsrc_IpsNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#539: FILE: ./hal/HalBtcOutSrc.h:539:
    +void EXhalbtcoutsrc_LpsNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#540: FILE: ./hal/HalBtcOutSrc.h:540:
    +void EXhalbtcoutsrc_ScanNotify(struct BTC_COEXIST * pBtCoexist, u8 type);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#541: FILE: ./hal/HalBtcOutSrc.h:541:
    +void EXhalbtcoutsrc_ConnectNotify(struct BTC_COEXIST * pBtCoexist, u8 action);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#543: FILE: ./hal/HalBtcOutSrc.h:543:
    +	struct BTC_COEXIST * pBtCoexist, enum RT_MEDIA_STATUS mediaStatus

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#545: FILE: ./hal/HalBtcOutSrc.h:545:
    +void EXhalbtcoutsrc_SpecialPacketNotify(struct BTC_COEXIST * pBtCoexist, u8 pktType);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#547: FILE: ./hal/HalBtcOutSrc.h:547:
    +	struct BTC_COEXIST * pBtCoexist, u8 *tmpBuf, u8 length

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#549: FILE: ./hal/HalBtcOutSrc.h:549:
    +void EXhalbtcoutsrc_HaltNotify(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#550: FILE: ./hal/HalBtcOutSrc.h:550:
    +void EXhalbtcoutsrc_PnpNotify(struct BTC_COEXIST * pBtCoexist, u8 pnpState);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#551: FILE: ./hal/HalBtcOutSrc.h:551:
    +void EXhalbtcoutsrc_Periodical(struct BTC_COEXIST * pBtCoexist);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#555: FILE: ./hal/HalBtcOutSrc.h:555:
    +void EXhalbtcoutsrc_DisplayBtCoexInfo(struct BTC_COEXIST * pBtCoexist);

Reviewed-by: Dan Carpenter <[email protected]>
Signed-off-by: Marco Cesati <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
fengguang pushed a commit to 0day-ci/linux that referenced this pull request Mar 16, 2021
This commit fixes the following checkpatch.pl errors:

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#57: FILE: ./hal/HalPhyRf_8723B.c:57:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#138: FILE: ./hal/HalPhyRf_8723B.c:138:
    +static void setCCKFilterCoefficient(struct DM_ODM_T * pDM_Odm, u8 CCKSwingIndex)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#162: FILE: ./hal/HalPhyRf_8723B.c:162:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#188: FILE: ./hal/HalPhyRf_8723B.c:188:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#363: FILE: ./hal/HalPhyRf_8723B.c:363:
    +	struct DM_ODM_T * pDM_Odm,

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#371: FILE: ./hal/HalPhyRf_8723B.c:371:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#412: FILE: ./hal/HalPhyRf_8723B.c:412:
    +void ConfigureTxpowerTrack_8723B(struct TXPWRTRACK_CFG * pConfig)

    ERROR:POINTER_LOCATION: "foo *		bar" should be "foo *bar"
    torvalds#440: FILE: ./hal/HalPhyRf_8723B.c:440:
    +	struct DM_ODM_T *		pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#551: FILE: ./hal/HalPhyRf_8723B.c:551:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#765: FILE: ./hal/HalPhyRf_8723B.c:765:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#872: FILE: ./hal/HalPhyRf_8723B.c:872:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1095: FILE: ./hal/HalPhyRf_8723B.c:1095:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1097: FILE: ./hal/HalPhyRf_8723B.c:1097:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1175: FILE: ./hal/HalPhyRf_8723B.c:1175:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1177: FILE: ./hal/HalPhyRf_8723B.c:1177:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1250: FILE: ./hal/HalPhyRf_8723B.c:1250:
    +void ODM_SetIQCbyRFpath(struct DM_ODM_T * pDM_Odm, u32 RFpath)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1253: FILE: ./hal/HalPhyRf_8723B.c:1253:
    +	struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1295: FILE: ./hal/HalPhyRf_8723B.c:1295:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo *		bar" should be "foo *bar"
    torvalds#1313: FILE: ./hal/HalPhyRf_8723B.c:1313:
    +	struct DM_ODM_T *		pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1333: FILE: ./hal/HalPhyRf_8723B.c:1333:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    torvalds#1363: FILE: ./hal/HalPhyRf_8723B.c:1363:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1387: FILE: ./hal/HalPhyRf_8723B.c:1387:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1492: FILE: ./hal/HalPhyRf_8723B.c:1492:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1700: FILE: ./hal/HalPhyRf_8723B.c:1700:
    +static void phy_LCCalibrate_8723B(struct DM_ODM_T * pDM_Odm, bool is2T)

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1787: FILE: ./hal/HalPhyRf_8723B.c:1787:
    +	struct DM_ODM_T * pDM_Odm = &pHalData->odmpriv;

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #1833: FILE: ./hal/HalPhyRf_8723B.c:1833:
    +		struct ODM_RF_CAL_T * pRFCalibrateInfo = &(pDM_Odm->RFCalibrateInfo);

    ERROR:POINTER_LOCATION: "foo * bar" should be "foo *bar"
    #2041: FILE: ./hal/HalPhyRf_8723B.c:2041:
    +void PHY_LCCalibrate_8723B(struct DM_ODM_T * pDM_Odm)

Reviewed-by: Dan Carpenter <[email protected]>
Signed-off-by: Marco Cesati <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
ojeda added a commit to ojeda/linux that referenced this pull request Nov 20, 2021
ddiss pushed a commit to ddiss/linux that referenced this pull request Jan 28, 2025
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request May 27, 2025
Running a modified trace-cmd record --nosplice where it does a mmap of the
ring buffer when '--nosplice' is set, caused the following lockdep splat:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 Not tainted
 ------------------------------------------------------
 trace-cmd/1113 is trying to acquire lock:
 ffff888100062888 (&buffer->mutex){+.+.}-{4:4}, at: ring_buffer_map+0x11c/0xe70

 but task is already holding lock:
 ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #5 (&cpu_buffer->mapping_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0xcf/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #4 (&mm->mmap_lock){++++}-{4:4}:
        __might_fault+0xa5/0x110
        _copy_to_user+0x22/0x80
        _perf_ioctl+0x61b/0x1b70
        perf_ioctl+0x62/0x90
        __x64_sys_ioctl+0x134/0x190
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #3 (&cpuctx_mutex){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0x325/0x7c0
        perf_event_init+0x52a/0x5b0
        start_kernel+0x263/0x3e0
        x86_64_start_reservations+0x24/0x30
        x86_64_start_kernel+0x95/0xa0
        common_startup_64+0x13e/0x141

 -> #2 (pmus_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0xb7/0x7c0
        cpuhp_invoke_callback+0x2c0/0x1030
        __cpuhp_invoke_callback_range+0xbf/0x1f0
        _cpu_up+0x2e7/0x690
        cpu_up+0x117/0x170
        cpuhp_bringup_mask+0xd5/0x120
        bringup_nonboot_cpus+0x13d/0x170
        smp_init+0x2b/0xf0
        kernel_init_freeable+0x441/0x6d0
        kernel_init+0x1e/0x160
        ret_from_fork+0x34/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (cpu_hotplug_lock){++++}-{0:0}:
        cpus_read_lock+0x2a/0xd0
        ring_buffer_resize+0x610/0x14e0
        __tracing_resize_ring_buffer.part.0+0x42/0x120
        tracing_set_tracer+0x7bd/0xa80
        tracing_set_trace_write+0x132/0x1e0
        vfs_write+0x21c/0xe80
        ksys_write+0xf9/0x1c0
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #0 (&buffer->mutex){+.+.}-{4:4}:
        __lock_acquire+0x1405/0x2210
        lock_acquire+0x174/0x310
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0x11c/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   &buffer->mutex --> &mm->mmap_lock --> &cpu_buffer->mapping_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cpu_buffer->mapping_lock);
                                lock(&mm->mmap_lock);
                                lock(&cpu_buffer->mapping_lock);
   lock(&buffer->mutex);

  *** DEADLOCK ***

 2 locks held by trace-cmd/1113:
  #0: ffff888106b847e0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x192/0x390
  #1: ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 stack backtrace:
 CPU: 5 UID: 0 PID: 1113 Comm: trace-cmd Not tainted 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 PREEMPT
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6e/0xa0
  print_circular_bug.cold+0x178/0x1be
  check_noncircular+0x146/0x160
  __lock_acquire+0x1405/0x2210
  lock_acquire+0x174/0x310
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x169/0x18c0
  __mutex_lock+0x192/0x18c0
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? function_trace_call+0x296/0x370
  ? __pfx___mutex_lock+0x10/0x10
  ? __pfx_function_trace_call+0x10/0x10
  ? __pfx___mutex_lock+0x10/0x10
  ? _raw_spin_unlock+0x2d/0x50
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x5/0x18c0
  ring_buffer_map+0x11c/0xe70
  ? do_raw_spin_lock+0x12d/0x270
  ? find_held_lock+0x2b/0x80
  ? _raw_spin_unlock+0x2d/0x50
  ? rcu_is_watching+0x15/0xb0
  ? _raw_spin_unlock+0x2d/0x50
  ? trace_preempt_on+0xd0/0x110
  tracing_buffers_mmap+0x1c4/0x3b0
  __mmap_region+0xd8d/0x1f70
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx___mmap_region+0x10/0x10
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? bpf_lsm_mmap_addr+0x4/0x10
  ? security_mmap_addr+0x46/0xd0
  ? lock_is_held_type+0xd9/0x130
  do_mmap+0x9d7/0x1010
  ? 0xffffffffc0370095
  ? __pfx_do_mmap+0x10/0x10
  vm_mmap_pgoff+0x20b/0x390
  ? __pfx_vm_mmap_pgoff+0x10/0x10
  ? 0xffffffffc0370095
  ksys_mmap_pgoff+0x2e9/0x440
  do_syscall_64+0x79/0x1c0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7fb0963a7de2
 Code: 00 00 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 76 5b 5d c3 0f 1f 00 48 8b 05 e1 9f 0d 00 64
 RSP: 002b:00007ffdcc8fb878 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb0963a7de2
 RDX: 0000000000000001 RSI: 0000000000001000 RDI: 0000000000000000
 RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
 R13: 00007ffdcc8fbe68 R14: 00007fb096628000 R15: 00005633e01a5c90
  </TASK>

The issue is that cpus_read_lock() is taken within buffer->mutex. The
memory mapped pages are taken with the mmap_lock held. The buffer->mutex
is taken within the cpu_buffer->mapping_lock. There's quite a chain with
all these locks, where the deadlock can be fixed by moving the
cpus_read_lock() outside the taking of the buffer->mutex.

Cc: [email protected]
Fixes: 117c392 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <[email protected]>
heftig pushed a commit to zen-kernel/zen-kernel that referenced this pull request Jun 19, 2025
commit c98cc97 upstream.

Running a modified trace-cmd record --nosplice where it does a mmap of the
ring buffer when '--nosplice' is set, caused the following lockdep splat:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 Not tainted
 ------------------------------------------------------
 trace-cmd/1113 is trying to acquire lock:
 ffff888100062888 (&buffer->mutex){+.+.}-{4:4}, at: ring_buffer_map+0x11c/0xe70

 but task is already holding lock:
 ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #5 (&cpu_buffer->mapping_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0xcf/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #4 (&mm->mmap_lock){++++}-{4:4}:
        __might_fault+0xa5/0x110
        _copy_to_user+0x22/0x80
        _perf_ioctl+0x61b/0x1b70
        perf_ioctl+0x62/0x90
        __x64_sys_ioctl+0x134/0x190
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #3 (&cpuctx_mutex){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0x325/0x7c0
        perf_event_init+0x52a/0x5b0
        start_kernel+0x263/0x3e0
        x86_64_start_reservations+0x24/0x30
        x86_64_start_kernel+0x95/0xa0
        common_startup_64+0x13e/0x141

 -> #2 (pmus_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0xb7/0x7c0
        cpuhp_invoke_callback+0x2c0/0x1030
        __cpuhp_invoke_callback_range+0xbf/0x1f0
        _cpu_up+0x2e7/0x690
        cpu_up+0x117/0x170
        cpuhp_bringup_mask+0xd5/0x120
        bringup_nonboot_cpus+0x13d/0x170
        smp_init+0x2b/0xf0
        kernel_init_freeable+0x441/0x6d0
        kernel_init+0x1e/0x160
        ret_from_fork+0x34/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (cpu_hotplug_lock){++++}-{0:0}:
        cpus_read_lock+0x2a/0xd0
        ring_buffer_resize+0x610/0x14e0
        __tracing_resize_ring_buffer.part.0+0x42/0x120
        tracing_set_tracer+0x7bd/0xa80
        tracing_set_trace_write+0x132/0x1e0
        vfs_write+0x21c/0xe80
        ksys_write+0xf9/0x1c0
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #0 (&buffer->mutex){+.+.}-{4:4}:
        __lock_acquire+0x1405/0x2210
        lock_acquire+0x174/0x310
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0x11c/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   &buffer->mutex --> &mm->mmap_lock --> &cpu_buffer->mapping_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cpu_buffer->mapping_lock);
                                lock(&mm->mmap_lock);
                                lock(&cpu_buffer->mapping_lock);
   lock(&buffer->mutex);

  *** DEADLOCK ***

 2 locks held by trace-cmd/1113:
  #0: ffff888106b847e0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x192/0x390
  #1: ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 stack backtrace:
 CPU: 5 UID: 0 PID: 1113 Comm: trace-cmd Not tainted 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 PREEMPT
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6e/0xa0
  print_circular_bug.cold+0x178/0x1be
  check_noncircular+0x146/0x160
  __lock_acquire+0x1405/0x2210
  lock_acquire+0x174/0x310
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x169/0x18c0
  __mutex_lock+0x192/0x18c0
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? function_trace_call+0x296/0x370
  ? __pfx___mutex_lock+0x10/0x10
  ? __pfx_function_trace_call+0x10/0x10
  ? __pfx___mutex_lock+0x10/0x10
  ? _raw_spin_unlock+0x2d/0x50
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x5/0x18c0
  ring_buffer_map+0x11c/0xe70
  ? do_raw_spin_lock+0x12d/0x270
  ? find_held_lock+0x2b/0x80
  ? _raw_spin_unlock+0x2d/0x50
  ? rcu_is_watching+0x15/0xb0
  ? _raw_spin_unlock+0x2d/0x50
  ? trace_preempt_on+0xd0/0x110
  tracing_buffers_mmap+0x1c4/0x3b0
  __mmap_region+0xd8d/0x1f70
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx___mmap_region+0x10/0x10
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? bpf_lsm_mmap_addr+0x4/0x10
  ? security_mmap_addr+0x46/0xd0
  ? lock_is_held_type+0xd9/0x130
  do_mmap+0x9d7/0x1010
  ? 0xffffffffc0370095
  ? __pfx_do_mmap+0x10/0x10
  vm_mmap_pgoff+0x20b/0x390
  ? __pfx_vm_mmap_pgoff+0x10/0x10
  ? 0xffffffffc0370095
  ksys_mmap_pgoff+0x2e9/0x440
  do_syscall_64+0x79/0x1c0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7fb0963a7de2
 Code: 00 00 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 76 5b 5d c3 0f 1f 00 48 8b 05 e1 9f 0d 00 64
 RSP: 002b:00007ffdcc8fb878 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb0963a7de2
 RDX: 0000000000000001 RSI: 0000000000001000 RDI: 0000000000000000
 RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
 R13: 00007ffdcc8fbe68 R14: 00007fb096628000 R15: 00005633e01a5c90
  </TASK>

The issue is that cpus_read_lock() is taken within buffer->mutex. The
memory mapped pages are taken with the mmap_lock held. The buffer->mutex
is taken within the cpu_buffer->mapping_lock. There's quite a chain with
all these locks, where the deadlock can be fixed by moving the
cpus_read_lock() outside the taking of the buffer->mutex.

Cc: [email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: 117c392 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
opsiff pushed a commit to deepin-community/kernel-rolling that referenced this pull request Jul 10, 2025
commit c98cc97 upstream.

Running a modified trace-cmd record --nosplice where it does a mmap of the
ring buffer when '--nosplice' is set, caused the following lockdep splat:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 Not tainted
 ------------------------------------------------------
 trace-cmd/1113 is trying to acquire lock:
 ffff888100062888 (&buffer->mutex){+.+.}-{4:4}, at: ring_buffer_map+0x11c/0xe70

 but task is already holding lock:
 ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #5 (&cpu_buffer->mapping_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0xcf/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #4 (&mm->mmap_lock){++++}-{4:4}:
        __might_fault+0xa5/0x110
        _copy_to_user+0x22/0x80
        _perf_ioctl+0x61b/0x1b70
        perf_ioctl+0x62/0x90
        __x64_sys_ioctl+0x134/0x190
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #3 (&cpuctx_mutex){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0x325/0x7c0
        perf_event_init+0x52a/0x5b0
        start_kernel+0x263/0x3e0
        x86_64_start_reservations+0x24/0x30
        x86_64_start_kernel+0x95/0xa0
        common_startup_64+0x13e/0x141

 -> #2 (pmus_lock){+.+.}-{4:4}:
        __mutex_lock+0x192/0x18c0
        perf_event_init_cpu+0xb7/0x7c0
        cpuhp_invoke_callback+0x2c0/0x1030
        __cpuhp_invoke_callback_range+0xbf/0x1f0
        _cpu_up+0x2e7/0x690
        cpu_up+0x117/0x170
        cpuhp_bringup_mask+0xd5/0x120
        bringup_nonboot_cpus+0x13d/0x170
        smp_init+0x2b/0xf0
        kernel_init_freeable+0x441/0x6d0
        kernel_init+0x1e/0x160
        ret_from_fork+0x34/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (cpu_hotplug_lock){++++}-{0:0}:
        cpus_read_lock+0x2a/0xd0
        ring_buffer_resize+0x610/0x14e0
        __tracing_resize_ring_buffer.part.0+0x42/0x120
        tracing_set_tracer+0x7bd/0xa80
        tracing_set_trace_write+0x132/0x1e0
        vfs_write+0x21c/0xe80
        ksys_write+0xf9/0x1c0
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #0 (&buffer->mutex){+.+.}-{4:4}:
        __lock_acquire+0x1405/0x2210
        lock_acquire+0x174/0x310
        __mutex_lock+0x192/0x18c0
        ring_buffer_map+0x11c/0xe70
        tracing_buffers_mmap+0x1c4/0x3b0
        __mmap_region+0xd8d/0x1f70
        do_mmap+0x9d7/0x1010
        vm_mmap_pgoff+0x20b/0x390
        ksys_mmap_pgoff+0x2e9/0x440
        do_syscall_64+0x79/0x1c0
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   &buffer->mutex --> &mm->mmap_lock --> &cpu_buffer->mapping_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cpu_buffer->mapping_lock);
                                lock(&mm->mmap_lock);
                                lock(&cpu_buffer->mapping_lock);
   lock(&buffer->mutex);

  *** DEADLOCK ***

 2 locks held by trace-cmd/1113:
  #0: ffff888106b847e0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x192/0x390
  #1: ffff888100a5f9f8 (&cpu_buffer->mapping_lock){+.+.}-{4:4}, at: ring_buffer_map+0xcf/0xe70

 stack backtrace:
 CPU: 5 UID: 0 PID: 1113 Comm: trace-cmd Not tainted 6.15.0-rc7-test-00002-gfb7d03d8a82f torvalds#551 PREEMPT
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6e/0xa0
  print_circular_bug.cold+0x178/0x1be
  check_noncircular+0x146/0x160
  __lock_acquire+0x1405/0x2210
  lock_acquire+0x174/0x310
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x169/0x18c0
  __mutex_lock+0x192/0x18c0
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? function_trace_call+0x296/0x370
  ? __pfx___mutex_lock+0x10/0x10
  ? __pfx_function_trace_call+0x10/0x10
  ? __pfx___mutex_lock+0x10/0x10
  ? _raw_spin_unlock+0x2d/0x50
  ? ring_buffer_map+0x11c/0xe70
  ? ring_buffer_map+0x11c/0xe70
  ? __mutex_lock+0x5/0x18c0
  ring_buffer_map+0x11c/0xe70
  ? do_raw_spin_lock+0x12d/0x270
  ? find_held_lock+0x2b/0x80
  ? _raw_spin_unlock+0x2d/0x50
  ? rcu_is_watching+0x15/0xb0
  ? _raw_spin_unlock+0x2d/0x50
  ? trace_preempt_on+0xd0/0x110
  tracing_buffers_mmap+0x1c4/0x3b0
  __mmap_region+0xd8d/0x1f70
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx___mmap_region+0x10/0x10
  ? ring_buffer_lock_reserve+0x99/0xff0
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? __pfx_ring_buffer_lock_reserve+0x10/0x10
  ? bpf_lsm_mmap_addr+0x4/0x10
  ? security_mmap_addr+0x46/0xd0
  ? lock_is_held_type+0xd9/0x130
  do_mmap+0x9d7/0x1010
  ? 0xffffffffc0370095
  ? __pfx_do_mmap+0x10/0x10
  vm_mmap_pgoff+0x20b/0x390
  ? __pfx_vm_mmap_pgoff+0x10/0x10
  ? 0xffffffffc0370095
  ksys_mmap_pgoff+0x2e9/0x440
  do_syscall_64+0x79/0x1c0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7fb0963a7de2
 Code: 00 00 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 76 5b 5d c3 0f 1f 00 48 8b 05 e1 9f 0d 00 64
 RSP: 002b:00007ffdcc8fb878 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb0963a7de2
 RDX: 0000000000000001 RSI: 0000000000001000 RDI: 0000000000000000
 RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
 R13: 00007ffdcc8fbe68 R14: 00007fb096628000 R15: 00005633e01a5c90
  </TASK>

The issue is that cpus_read_lock() is taken within buffer->mutex. The
memory mapped pages are taken with the mmap_lock held. The buffer->mutex
is taken within the cpu_buffer->mapping_lock. There's quite a chain with
all these locks, where the deadlock can be fixed by moving the
cpus_read_lock() outside the taking of the buffer->mutex.

Cc: [email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: 117c392 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
(cherry picked from commit 2d6a6cf)
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